differential noise
 

Hey guys and gals,
I just installed a set of 4.10 gears in my 07 Mustang. I set the backlash to the proper specs and it had a good wear pattern when I painted the marking compound on the ring gear.
The problem that I am having is a strange noise. It is not howling or whining though. It sounds exactly like a power steering pump that doesn't have enough fluid in it while you are trying to turn the wheel.
Have any of you ever encountered anything like this???
Mike

We have found gears that were out of round and varied in thickness from the chinese sources. Saw this in the problems friends were having with their rearend setups. Were these American gears?

Curtis

Differential noise
 

If you installed a posi unit you may need to use a synthetic oil to quiet the clutches. I had the same problem and changing to a synthetic oil solved it.

did you also change your bearings? and seals? i have changed many
gears and its always the gears making noise but not like a steering
unit, yea which gears did you use? :?

The answer hasn't come yet, but if you used the old pinion bearings or if you have the pinion too tight you could get this noise. I have heard this noise when a person didn't use a new crush sleeve and put too much torque on the pinion nut. Old bearings should have 15 Inch lbs. to spin the pinion no ring gear installed, 18 to 22 inch lbs with new bearings, no ring gear installed.
Believe it or not i have used many gears from Quick performance, they are made in Italy by the same factory that makes many of the European gears. They cost $110.00 per set and i've installed them in everything from a 4.70 dragster to a 3500lb S/ST car and have never broke one yet (knock on wood) I not suggesting that you didn't check all these things mentioned, but it's just a thought.

Zip.

I'm assuming that since this is a 07 mustang that it has a factory posi and not a spool.
Ford posi's units need that really stinky friction modifer junk put in there, if you just filled it up with regular lube then this may very well be you problem.
If you dont have it in the rearend it will make all kinds of funny noises popping, chattering and whining.
The stuff you need is at the dealership don't use the friction modifer stuff at autozone, it will not work.
Also the factory recommends a snythetic lube, I believe its a 75w-140 and its not cheap either @ around $15 quart.
NOTE: I always use more than what the factory recommends - usually 12 to 16 onces of the stinky stuff will do the trick.
Goodluck, Charles

Thank you all for the advice guys! This is great!
The gears are actually factory Ford gears. I reused the factory posi center section, and reused my original pinion bearings. I did use a brand new crush collar when I put it back together along with a brand new seal that was included with the installation kit.
One good point that was brought up was the fact that I did not use synthetic oil just regular gear oil and I used 4 ounces of the autozone friction modifier. My factory service manual says to use 4 ounces of this friction modifier aditive but I didn't think that it would matter much about the brand. I will go to the dealer and get some of that along with SYNTHETIC gear oil.
As soon as I try this, then I will let you all know what I came up with.
Thanks again for everything guys! You have been a BIG help along with giving ole Mike a glimmer of hope that I may have actually installed everything correctly!!!!!! This is the first time that I have ever attempted a ring and pinion swap!

Hey Mike,
Thanks for replying back, I hate when people ask for opinions and then you never hear what they found or what they think. Let us know if that lines out your rear. Helps us all learn things.

Curtis

Curtis,
Well, I just put the car all back together and it makes a horrible noise when you let off of the accelerator. :roll: I obviously don't have something right so I guess it is back to the drawing board. It doesn't seem to make the dry power steering pump noise while you are accelerating but it definitely growls at you when you are slowing down!
Mike

Are you checking the wear pattern on the drive side of the tooth or the coast side? It sounds like a pinion depth problem to me. Nick