{"id":105066,"date":"2026-03-05T15:04:40","date_gmt":"2026-03-05T23:04:40","guid":{"rendered":"https:\/\/www.racingjunk.com\/news\/?p=105066"},"modified":"2026-03-05T15:04:40","modified_gmt":"2026-03-05T23:04:40","slug":"elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential","status":"publish","type":"post","link":"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/","title":{"rendered":"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential"},"content":{"rendered":"<div data-carousel-extra='{\"blog_id\":1,\"permalink\":\"https:\\\/\\\/www.racingjunk.com\\\/news\\\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\\\/\"}' id='gallery-1' class='gallery galleryid-105066 gallery-columns-3 gallery-size-thumbnail'><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/1-169\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/1-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" aria-describedby=\"gallery-1-105075\" data-attachment-id=\"105075\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/1-169\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/1-scaled-e1772751848524.jpg\" data-orig-size=\"640,480\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;1.5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 14&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1772619173&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.7&quot;,&quot;iso&quot;:&quot;160&quot;,&quot;shutter_speed&quot;:&quot;0.016666666666667&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt; &lt;a class=&quot;click__begin&quot;&gt;Click Here to Begin Slideshow&lt;\/a&gt;&lt;\/p&gt;\n&lt;p&gt;It\u2019s no secret that an open differential (fondly referred to as a \u201cpeg leg\u201d in some circles) just doesn\u2019t cut it in a high-performance application. Having one tire go up in smoke while the other does nothing won\u2019t get you down or around the track in short order. That\u2019s why spools and positractions are so common in motorsports.  While spools have their place, for the majority of dual duty drag cars and other competitive motorsport applications, a differential of some sort just makes solid sense. Today, there are sorts of choices for a \u201cpositraction\u201d differential (limited slip, no spin, locker, etc). All of those differentials use diverse technology (some similar, some completely different) in order to lock the wheels of the car up when required and to automatically release one of the wheels when not required. Many of these differentials use some form of internal clutch or friction material pack. These clutches simply wear with age, so basically, the more they\u2019re worked the shorter the life span.\u00a0 There\u2019s more too:\u00a0 Some of those differentials can prove to be rather abrupt (!) when they do their job.\u00a0 If you have Huge \u201cX\u201d Large power in the car, you have to pay attention with some differential configurations when the roads are damp or the pavement is cold. Let\u2019s just say, when a beefy old school differential locks or unlocks, you usually know it.\u00a0 You can hear it and you can regularly feel it.  On the flipside of the coin is an innovative Eaton product, and that\u2019s the Detroit Truetrac. This is a differential that uses absolutely no clutches or friction materials in operation. Instead, it relies upon a set of helical cut gears to lock and unlock the differential. \u00a0The Truetrac was actually introduced in the Seventies and over the years, Eaton has constantly tweaked and refined the technology.\u00a0 It is very simple in design (and keep in mind in world of motorsports, simple is definitely good). Basically, it\u2019s a maintenance free rear end. Plus, the overall design is extremely stout (more later).\u00a0 An added bonus is the fact it requires no special lubricants or friction modifier additives to function properly either.  It&amp;#8217;s important to understand the Truetrac is a helical gear, limited slip differential. It is not a \u201clocker\u201d nor is it a \u201cpositraction\u201d. Eaton notes the Truetrac operates on the principle of \u201ctorque biasing\u201d. Typically, a Truetrac will provide approximately three to three and a half times the torque of the spinning wheel to the wheel that has traction.\u00a0 According to Eaton:  \u201cThe Truetrac differential operates as a conventional open differential under normal driving conditions. It allows one wheel to spin faster or spin slower as necessary. When a wheel encounters a loss of traction or the terrain changes, internal gear separation forces take effect and in turn, they transfer torque to the high-traction wheel. The helical-shaped gears mesh with increasing force until wheel spin is slowed or completely stopped. When the vehicle exits the low traction situation, the differential resumes normal operation.\u201d  This Eaton video shows the basic differences between a common \u201cdifferential\u201d versus a Truetrac. It also illustrates how the Truetrac works:  &lt;a href=&quot;https:\/\/videos.eaton.com\/detail\/videos\/differentials\/video\/2196423811001\/eaton-truetrac-limited-slip-differential:-how-it-works-applications?autoStart=true&amp;amp;page=3&quot;&gt;https:\/\/videos.eaton.com\/detail\/videos\/differentials\/video\/2196423811001\/eaton-truetrac-limited-slip-differential:-how-it-works-applications?autoStart=true&amp;amp;page=3&lt;\/a&gt;  By design, the Truetrac will operate seamlessly on the street. Basically, it has no bad manners and you won\u2019t feel anything grave either. Eaton tells us that in a drag racing application, the car will hook and go straight in a repeatable fashion. When you launch the car, this temporarily creates a very high gear separation within the Truetrac. This forces both wheels to drive in unison, which in turn moves the car forward as efficiently as possible. Essentially, both wheels are locked together and provide identical traction. And that\u2019s good news for us.  There\u2019s more too, when it comes to power and torque capabilities from Eaton:  \u201cThe Detroit Truetrac is designed to handle more torque (power) than the axle shafts it drives. Horsepower has little influence on the differential since it is more of a function of engine RPM. Each model of Truetrac is designed to unique torque capacity specifications; however, they are all developed to handle the extreme torque loads typical in professional racing and military applications. The torque limit is largely limited by the \u201cbarrel\u201d diameter (the inside diameter of the ring gear) but is also limited in c-clip models by the reduced pinion gear sets due to the c-clip installation pocket. Since these parameters are dictated by the axle design and ring gear strength, the Truetrac differential should not be the limiting component in the axle\u2019s torque capacity.\u201d  When it comes to construction, the Detroit Truetrac is built with a forged or billet, heat-treated and fully-machined case. The large internal helical gears are extreme quality. End caps are cast and they too exhibit fabulous machining. Fasteners are Grade 8, and an important note:\u00a0 There are no huge \u201copen windows\u201d in the case (when compared to a conventional limited slip differential). Obviously, this leads to an exceptionally strong case. All driveline loads are distributed over a large amount of material (gear teeth). This helps create the high torque handling capability. Further to this, Eaton notes:  \u201cFrom a high-level\u00a0system view, the units are constructed similarly to an open differential except all gears are helical and the \u201cpinion\u201d gear is split into two intermeshed gears. Because of the three gear tooth mesh interfaces, the design must have lash. While all Truetracs (and helical gear differentials in general) have internal lash, units with preload are less noticeable. Typically, Truetracs have a maximum lash of three to four degrees side-to-side between gears. This is normal and required for the superior torque transfer design of the product.\u201d  For applications, Eaton offers Truetracs for a huge range of popular high-performance vehicles common in our industry. Included in the mix are the following (but certainly not limited to these either \u2013 there\u2019s a huge number of Truetrac applications for other combinations as well including modern musclecars): Dana 60, Mopar 8-3\/4, Ford 9-inch, Ford 8.8-inch, GM (Chevy) 12 bolt, GM 10 bolt (8.5-inch) and GM 10 bolt (8.20-inch).\u00a0 Within this mix, Truetracs are available for several different production and even non-production axle spline configurations. Case-in-point, the 12 bolt Truetrac shown in the accompanying photos is designed to work for 33-spline aftermarket axles with a 1.41-inch diameter axle shaft. FYI, stock for a 12 bolt is a 31-spline axle with a 1.29-inch diameter axle shaft.\u00a0 In some cases, the desired gear ratio determines which Truetrac to order. For example, a 4.10:1 and up 12 bolt uses one particular Truetrac part number while a 3.08:1 to 3.90:1 example uses another. You can download Eaton\u2019s complete differential application guide right here:  &lt;a href=&quot;https:\/\/www.eaton.com\/content\/dam\/eaton\/products\/differentials-traction-control\/eaton-performance-differential-application-guide-en.pdf&quot;&gt;https:\/\/www.eaton.com\/content\/dam\/eaton\/products\/differentials-traction-control\/eaton-performance-differential-application-guide-en.pdf&lt;\/a&gt;  In the photos (and captions) that follow, we\u2019ll give you a close look at a 33-spline 12 bolt Truetrac. Bottom line here is, if you\u2019re looking for an extremely beefy differential, this setup might be right for you.\u00a0 It\u2019s certainly no \u201cpeg leg\u201d!\u00a0 Check it out:&lt;\/p&gt;\n&lt;p&gt; &lt;a class=&quot;click__begin&quot;&gt;Click Here to Begin Slideshow&lt;\/a&gt;&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/1-300x225.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/1-1024x768.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105075'>\n\t\t\t\t <a class=\"click__begin\">Click Here to Begin Slideshow<\/a>\n\nIt\u2019s no secret that an open differential (fondly referred to as a \u201cpeg leg\u201d in some circles) just doesn\u2019t cut it in a high-performance application. Having one tire go up in smoke while the other does nothing won\u2019t get you down or around the track in short order. That\u2019s why spools and positractions are so common in motorsports.  While spools have their place, for the majority of dual duty drag cars and other competitive motorsport applications, a differential of some sort just makes solid sense. Today, there are sorts of choices for a \u201cpositraction\u201d differential (limited slip, no spin, locker, etc). All of those differentials use diverse technology (some similar, some completely different) in order to lock the wheels of the car up when required and to automatically release one of the wheels when not required. Many of these differentials use some form of internal clutch or friction material pack. These clutches simply wear with age, so basically, the more they\u2019re worked the shorter the life span.\u00a0 There\u2019s more too:\u00a0 Some of those differentials can prove to be rather abrupt (!) when they do their job.\u00a0 If you have Huge \u201cX\u201d Large power in the car, you have to pay attention with some differential configurations when the roads are damp or the pavement is cold. Let\u2019s just say, when a beefy old school differential locks or unlocks, you usually know it.\u00a0 You can hear it and you can regularly feel it.  On the flipside of the coin is an innovative Eaton product, and that\u2019s the Detroit Truetrac. This is a differential that uses absolutely no clutches or friction materials in operation. Instead, it relies upon a set of helical cut gears to lock and unlock the differential. \u00a0The Truetrac was actually introduced in the Seventies and over the years, Eaton has constantly tweaked and refined the technology.\u00a0 It is very simple in design (and keep in mind in world of motorsports, simple is definitely good). Basically, it\u2019s a maintenance free rear end. Plus, the overall design is extremely stout (more later).\u00a0 An added bonus is the fact it requires no special lubricants or friction modifier additives to function properly either.  It&#8217;s important to understand the Truetrac is a helical gear, limited slip differential. It is not a \u201clocker\u201d nor is it a \u201cpositraction\u201d. Eaton notes the Truetrac operates on the principle of \u201ctorque biasing\u201d. Typically, a Truetrac will provide approximately three to three and a half times the torque of the spinning wheel to the wheel that has traction.\u00a0 According to Eaton:  \u201cThe Truetrac differential operates as a conventional open differential under normal driving conditions. It allows one wheel to spin faster or spin slower as necessary. When a wheel encounters a loss of traction or the terrain changes, internal gear separation forces take effect and in turn, they transfer torque to the high-traction wheel. The helical-shaped gears mesh with increasing force until wheel spin is slowed or completely stopped. When the vehicle exits the low traction situation, the differential resumes normal operation.\u201d  This Eaton video shows the basic differences between a common \u201cdifferential\u201d versus a Truetrac. It also illustrates how the Truetrac works:  <a href=\"https:\/\/videos.eaton.com\/detail\/videos\/differentials\/video\/2196423811001\/eaton-truetrac-limited-slip-differential:-how-it-works-applications?autoStart=true&amp;page=3\">https:\/\/videos.eaton.com\/detail\/videos\/differentials\/video\/2196423811001\/eaton-truetrac-limited-slip-differential:-how-it-works-applications?autoStart=true&amp;page=3<\/a>  By design, the Truetrac will operate seamlessly on the street. Basically, it has no bad manners and you won\u2019t feel anything grave either. Eaton tells us that in a drag racing application, the car will hook and go straight in a repeatable fashion. When you launch the car, this temporarily creates a very high gear separation within the Truetrac. This forces both wheels to drive in unison, which in turn moves the car forward as efficiently as possible. Essentially, both wheels are locked together and provide identical traction. And that\u2019s good news for us.  There\u2019s more too, when it comes to power and torque capabilities from Eaton:  \u201cThe Detroit Truetrac is designed to handle more torque (power) than the axle shafts it drives. Horsepower has little influence on the differential since it is more of a function of engine RPM. Each model of Truetrac is designed to unique torque capacity specifications; however, they are all developed to handle the extreme torque loads typical in professional racing and military applications. The torque limit is largely limited by the \u201cbarrel\u201d diameter (the inside diameter of the ring gear) but is also limited in c-clip models by the reduced pinion gear sets due to the c-clip installation pocket. Since these parameters are dictated by the axle design and ring gear strength, the Truetrac differential should not be the limiting component in the axle\u2019s torque capacity.\u201d  When it comes to construction, the Detroit Truetrac is built with a forged or billet, heat-treated and fully-machined case. The large internal helical gears are extreme quality. End caps are cast and they too exhibit fabulous machining. Fasteners are Grade 8, and an important note:\u00a0 There are no huge \u201copen windows\u201d in the case (when compared to a conventional limited slip differential). Obviously, this leads to an exceptionally strong case. All driveline loads are distributed over a large amount of material (gear teeth). This helps create the high torque handling capability. Further to this, Eaton notes:  \u201cFrom a high-level\u00a0system view, the units are constructed similarly to an open differential except all gears are helical and the \u201cpinion\u201d gear is split into two intermeshed gears. Because of the three gear tooth mesh interfaces, the design must have lash. While all Truetracs (and helical gear differentials in general) have internal lash, units with preload are less noticeable. Typically, Truetracs have a maximum lash of three to four degrees side-to-side between gears. This is normal and required for the superior torque transfer design of the product.\u201d  For applications, Eaton offers Truetracs for a huge range of popular high-performance vehicles common in our industry. Included in the mix are the following (but certainly not limited to these either \u2013 there\u2019s a huge number of Truetrac applications for other combinations as well including modern musclecars): Dana 60, Mopar 8-3\/4, Ford 9-inch, Ford 8.8-inch, GM (Chevy) 12 bolt, GM 10 bolt (8.5-inch) and GM 10 bolt (8.20-inch).\u00a0 Within this mix, Truetracs are available for several different production and even non-production axle spline configurations. Case-in-point, the 12 bolt Truetrac shown in the accompanying photos is designed to work for 33-spline aftermarket axles with a 1.41-inch diameter axle shaft. FYI, stock for a 12 bolt is a 31-spline axle with a 1.29-inch diameter axle shaft.\u00a0 In some cases, the desired gear ratio determines which Truetrac to order. For example, a 4.10:1 and up 12 bolt uses one particular Truetrac part number while a 3.08:1 to 3.90:1 example uses another. You can download Eaton\u2019s complete differential application guide right here:  <a href=\"https:\/\/www.eaton.com\/content\/dam\/eaton\/products\/differentials-traction-control\/eaton-performance-differential-application-guide-en.pdf\">https:\/\/www.eaton.com\/content\/dam\/eaton\/products\/differentials-traction-control\/eaton-performance-differential-application-guide-en.pdf<\/a>  In the photos (and captions) that follow, we\u2019ll give you a close look at a 33-spline 12 bolt Truetrac. Bottom line here is, if you\u2019re looking for an extremely beefy differential, this setup might be right for you.\u00a0 It\u2019s certainly no \u201cpeg leg\u201d!\u00a0 Check it out:\n\n <a class=\"click__begin\">Click Here to Begin Slideshow<\/a>\n\t\t\t\t<\/figcaption><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/2-154\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/2-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential\" aria-describedby=\"gallery-1-105067\" data-attachment-id=\"105067\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/2-154\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/2-scaled.jpg\" data-orig-size=\"2560,1920\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;1.5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 14&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1772619208&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.7&quot;,&quot;iso&quot;:&quot;160&quot;,&quot;shutter_speed&quot;:&quot;0.016666666666667&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt; When you take a quick glance at the Eaton Truetrac, you\u2019ll quickly note the entire main case is machined. More in the next photo:&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/2-300x225.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/2-1024x768.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105067'>\n\t\t\t\t When you take a quick glance at the Eaton Truetrac, you\u2019ll quickly note the entire main case is machined. More in the next photo:\n\t\t\t\t<\/figcaption><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/3-143\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/3-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential\" aria-describedby=\"gallery-1-105068\" data-attachment-id=\"105068\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/3-143\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/3-scaled.jpg\" data-orig-size=\"2560,1920\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;1.5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 14&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1772619288&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.7&quot;,&quot;iso&quot;:&quot;160&quot;,&quot;shutter_speed&quot;:&quot;0.016666666666667&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;While most other differentials are designed with huge windows allowing access to the internals, the Truetrac is almost fully enclosed. Clearly, this configuration isn\u2019t going to deflect anywhere under load.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/3-300x225.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/3-1024x768.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105068'>\n\t\t\t\tWhile most other differentials are designed with huge windows allowing access to the internals, the Truetrac is almost fully enclosed. Clearly, this configuration isn\u2019t going to deflect anywhere under load.\n\t\t\t\t<\/figcaption><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon portrait'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/4-128\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/4-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential\" aria-describedby=\"gallery-1-105069\" data-attachment-id=\"105069\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/4-128\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/4-scaled.jpg\" data-orig-size=\"1920,2560\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;1.5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 14&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1772619334&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.7&quot;,&quot;iso&quot;:&quot;160&quot;,&quot;shutter_speed&quot;:&quot;0.016666666666667&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;On one side, there\u2019s an opening for what amounts to a load button for the axles. This allows access to the c-clips for axles with that configuration.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/4-225x300.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/4-768x1024.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105069'>\n\t\t\t\tOn one side, there\u2019s an opening for what amounts to a load button for the axles. This allows access to the c-clips for axles with that configuration.\n\t\t\t\t<\/figcaption><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/5-105\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/5-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential\" aria-describedby=\"gallery-1-105070\" data-attachment-id=\"105070\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/5-105\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/5-scaled.jpg\" data-orig-size=\"2560,1870\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;1.5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 14&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1772619563&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.7&quot;,&quot;iso&quot;:&quot;125&quot;,&quot;shutter_speed&quot;:&quot;0.016666666666667&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt; On each end of the case, you\u2019ll find a set of cast and machined end plates. This provides access to the helical internal gears.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/5-300x219.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/5-1024x748.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105070'>\n\t\t\t\t On each end of the case, you\u2019ll find a set of cast and machined end plates. This provides access to the helical internal gears.\n\t\t\t\t<\/figcaption><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/6-84\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/6-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential\" aria-describedby=\"gallery-1-105071\" data-attachment-id=\"105071\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/6-84\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/6.jpg\" data-orig-size=\"1419,583\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;(Credit Eaton Corporation):  This photo from the folks at Eaton shows how the helical gear arrangement works inside the Truetrac.  When your car is launched, this creates a very high gear separation within the Truetrac. This forces both wheels to drive together, which in turn moves the car forward as efficiently as possible. Essentially, both wheels are locked together and provide identical traction.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/6-300x123.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/6-1024x421.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105071'>\n\t\t\t\t(Credit Eaton Corporation):  This photo from the folks at Eaton shows how the helical gear arrangement works inside the Truetrac.  When your car is launched, this creates a very high gear separation within the Truetrac. This forces both wheels to drive together, which in turn moves the car forward as efficiently as possible. Essentially, both wheels are locked together and provide identical traction.\n\t\t\t\t<\/figcaption><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/7-72\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/7-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential\" aria-describedby=\"gallery-1-105072\" data-attachment-id=\"105072\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/7-72\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/7-scaled.jpg\" data-orig-size=\"2560,1920\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;1.5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 14&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1772619587&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.7&quot;,&quot;iso&quot;:&quot;125&quot;,&quot;shutter_speed&quot;:&quot;0.016666666666667&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;Note the fasteners \u2013 they\u2019re all Grade 8.  &lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/7-300x225.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/7-1024x768.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105072'>\n\t\t\t\tNote the fasteners \u2013 they\u2019re all Grade 8.  \n\t\t\t\t<\/figcaption><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/8-62\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/8-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential\" aria-describedby=\"gallery-1-105073\" data-attachment-id=\"105073\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/8-62\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/8-scaled.jpg\" data-orig-size=\"2560,1920\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;1.5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 14&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1772619649&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.7&quot;,&quot;iso&quot;:&quot;64&quot;,&quot;shutter_speed&quot;:&quot;0.016666666666667&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;Because there are no clutches, there is no need for a special positraction fluid or special additives of any sort. Good old fashioned conventional (non-synthetic) gear lube will work just fine.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/8-300x225.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/8-1024x768.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105073'>\n\t\t\t\tBecause there are no clutches, there is no need for a special positraction fluid or special additives of any sort. Good old fashioned conventional (non-synthetic) gear lube will work just fine.\n\t\t\t\t<\/figcaption><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/9-48\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/9-150x150.jpg\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differential\" aria-describedby=\"gallery-1-105074\" data-attachment-id=\"105074\" data-permalink=\"https:\/\/www.racingjunk.com\/news\/elegant-engineering-inside-eatons-efficient-detroit-truetrac-differential\/9-48\/\" data-orig-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/9-scaled.jpg\" data-orig-size=\"2560,1920\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;1.5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 14&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1772619701&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.7&quot;,&quot;iso&quot;:&quot;160&quot;,&quot;shutter_speed&quot;:&quot;0.016666666666667&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Elegant Engineering: Inside Eaton\u2019s Efficient Detroit Truetrac Differentia\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;This particular Truetrac is built for a 12 bolt Chevy with 33-spline aftermarket axles. This means the axle shaft diameter is 1.41-inches (up from a stock 31-spline at 1.29-inches). See the text for more info along with an Eaton application link.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/9-300x225.jpg\" data-large-file=\"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/9-1024x768.jpg\" \/><\/a>\n\t\t\t<\/div>\n\t\t\t\t<figcaption class='wp-caption-text gallery-caption' id='gallery-1-105074'>\n\t\t\t\tThis particular Truetrac is built for a 12 bolt Chevy with 33-spline aftermarket axles. This means the axle shaft diameter is 1.41-inches (up from a stock 31-spline at 1.29-inches). See the text for more info along with an Eaton application link.\n\t\t\t\t<\/figcaption><\/figure>\n\t\t<\/div>\n\n","protected":false},"excerpt":{"rendered":"<div class=\"mh-excerpt\"><p>It\u2019s no secret that an open differential (fondly referred to as a \u201cpeg leg\u201d in some circles) just doesn\u2019t cut it in a high-performance application. Having one tire go up in smoke while the other does nothing won\u2019t get you down or around the track in short order. That\u2019s why spools and positractions are so common in motorsports.<\/p>\n<\/div>","protected":false},"author":20,"featured_media":105075,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[5011,17,11,3464,3470,4879,3698,5010],"tags":[3391,3089,4008,281,41,1632,461,13134,321],"class_list":["post-105066","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-chassis-suspension","category-guest-column","category-how-tos","category-junkyard-blog","category-news","category-slideshow","category-tech","category-tires-and-wheels","tag-detroit","tag-fasteners","tag-guest-column","tag-how-to","tag-news","tag-racing","tag-tech-tips-2","tag-tru-trac","tag-wayne-scraba"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2026\/03\/1-scaled-e1772751848524.jpg","jetpack_shortlink":"https:\/\/wp.me\/p42YSK-rkC","jetpack_sharing_enabled":true,"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/105066","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/comments?post=105066"}],"version-history":[{"count":1,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/105066\/revisions"}],"predecessor-version":[{"id":105076,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/105066\/revisions\/105076"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media\/105075"}],"wp:attachment":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media?parent=105066"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/categories?post=105066"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/tags?post=105066"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}