HELP I have a narrowed rear end leaking oil at vent tube!
 

I have a 63 olds GM narrowed rear end on my street driven Gasser. I can not figure out why it is leaking oil out of vent tube? It is not overfilled. It only leaks when I drive it 5 miles or more. Axles are less than 8" in length. any ideas? thanks

That is a good question, mine does the same thing. I dont think it is overfilled and it is an Aerospace modular alum rear.

I hope someone smart can help us...lol...

What weight of gear oil are you using ? Try putting a peice of rubber hose as an extension between the housing and the vent fitting and raise it up, bet it stops.

Vent leak
 

Yes and just being a smaller area to work in there is less area for the pressure being built up at cold temperatures also. Try the rubber hose length trick....that should solve it as long as you go up with it. Or you might need another vent hole OR larger vent diameter hole.

When the oil warms it tends to become more like a liquid instead of a syrup when cold. When it is thick it could be clogging the vent and pressure builds then blows through when too much pressure builds behind the thick oil. Then when the fluid thins out from the heat this trouble stops because the oil drips off faster.

See how it goes. Jim

I might try making the hole larger, I already tried a piece of 1/4 rubber hose about 10" long straight up attached to my chute mount. That sucker still runs right out the vent.

I am planning a gear change over the winter, so I can also check and make sure the hole isnt partially blocked on the inside and try it again with new gear oil.

Thanks guys

I've had the same problem and i noticed that on the s&w housings that the fitting is 1/8" pipe but the actual hole is much smaller than the inside diameter of the fitting. I dont know if this is the problem but on a stock 9" the hole is full size. almost 1/4". Ive raised the vent with a hose and installed a 1/8" screen fitting (f/nos kit)to fix, if that dont work i'm gunna drill out the hole to full size and try that. I did notice that s/w puts the vent in the center area and stock fords have it in the axle tubes.

vent tube trouble
 

Yes if you can make it bigger that will almost always work. Larger hole will have less air speed releving the pressure in the housing. It acts like a venture in a carb. or when you put a small nozzle on a water hose etc. logical thinking...just have to solve the problem...:) Jim

Move the vent to area where the housing meet the axle tube. If your vent tube is on the housing, turbulents from the gear will throw gear oil and force air out the vent.

That makes perfect sense. My vent is right above the ring gear. Way to go Aerospace...lol...

Thank you

rearend
 

did you say your axles are only 8 inches long, Id love to see those