I put new output shaft seals on my transmission about 10K miles ago. When I pulled the engine for overhaul I saw they were leaking...again. Is there something else that could be going bad in the tranny to cause these to leak? Any suggestions? Thanks!

Click to view attachment

The seal runs on the smooth surface of the output flange. Is the flange sealing area nice and smooth or is it all gnarled up?

Or perhaps did you install them too deep or too shallow so the rubber isnt riding on the smooth surface?

I am finding on rebuilding stuff these days the new seals are NOT the same depth as the factory ones. I found some of the old trans flange seals for mine but they were still not as deep as the factory one. It is real easy to get the seal in too deep with the new ones.

Make sure the breather vent is open and oriented correctly. Pressure build up will make the seals seep.

Agree: Vent, depth of seal, flange surface.

Depth is just flush with where the bore starts (there is a little step down to it).

If your flanges are pitted where the seal contacts, or even grimy, they wont work. Let me know, I have a bunch of them lying around and can likely hook you up. Removal is easy with impact driver. 19ft/lbs is all you need on install.

Vent is easy to remove and clean out.

Thanks for all the responses. I'll order a new set, inspect/clean the flanges, install new ones even with the bore step and clean the vent.

Add some Transmission lube to the sealing surface when installing. Without this, the seal will wear our quickly possibly putting a groove in the output flange where the seal rides

Good information guys, I'm having the same issue right now. Where is the best place to get the seal from? Does anyone sell it not in a kit?

Got mine from Auto Atlanta. Good quality.

Support out friends.

Go to www.gprparts.com and type 99911318340 as a part number

Well I can say the seals I got from GPR are much better quality than the ones I took off, probably the reason it leaks. The old ones came in a kit I bought a couple years ago. What is the best way to hammer on the new ones? Should I get a seal driver kit? Can't remember what I did in the past...

Also I thought I put the right level of trans fluid in, but a steady stream is leaking out when I pulled the drive flange out, does that mean its over filled? The nose of the car is still on the ground, so its not level.

To start it, I used a piece of wood that spanned the width of the seal to start it. I finished the install with a section of PVC pipe that sat on the seal. The other point of discussion is whether to stop the depth of the seal at the shoulder of the tranny case or a bit lower than the shoulder of the tranny case. Your mileage may vary. I installed a pair in 2014, and they were domestic manufacture closeout from Rock Auto. The best check for that would be to compare the old seal height with the new seal height and this may help you figure whether you are leaving it at the case shoulder height or deeper. The other way to determine this is to look at the halfshaft and see where the polished surface exists. That polished surface is what that seal should be "riding on." Mine were installed about 1/8" inch below the shoulder and I have not had any leaks. The domestic seals were shorter in height than the old ones (German). Your fluid level is fine. the amount of fluid that leaks out is a ragful (less than a couple of ounces).