Stubborn Transmission leak

[MVU2ORC]

2001 XJ 2wd. I have been fighting a leak at the rear transmission output seal. Have replaced 3 times now in the last year. The last time I replaced the slip yoke as it appear to be worn. That seemed to last the longest but know the leak is back worse than ever. Is it possible the driveshaft is out of balance slightly? Any ideas would be appreciated. Thanks

 

[Unclewolverine]

Yes a driveshaft cam be un balanced but it rare and would vibrate badly. Have you replaced the tail shaft bushing?

 

[Tim_MN]

Are you installing top quality seals ? Are you pre-lubing the seal when installing ? Are the surfaces the seal rides on clean and extremely smooth ?

 

[MVU2ORC]

Yes a driveshaft cam be un balanced but it rare and would vibrate badly. Have you replaced the tail shaft bushing?

No vibrations. I have only replaced the output shaft seal. Is the tail shaft bushing the same thing as the extension housing seal?

 

[MVU2ORC]

Are you installing top quality seals ? Are you pre-lubing the seal when installing ? Are the surfaces the seal rides on clean and extremely smooth ?

Seal is from local supply house, what brand would you suggest? I don’t remember if I lubed them, but will when I do the next one. The surfaces appear to be clean.

 

[Unclewolverine]

Not super familiar with the aw4 2wd but it should have a bronze bushing in the tailshaft behind the seal. They usually have to be pressed in by a machine shop.

 

[Dragonslayer]

Extension Housing Bushing. I've done several of these. With the engine shut down, put
the transmission in Neutral, grab the driveshaft with your hand near the forward U-Joint
and wriggle it. If the driveshaft wobbles by more than, say 1/16", then you need to
change the Extension Housing Bushing. The bushing is not made of bronze as was
mentioned earlier. It is a babbitt bearing - much like an engine camshaft bearing.
Getting the housing off of the transmission can be a bear as sometimes the sealant
used is stubborn with separating. I use a few whacks with a plastic-face dead blow hammer and copious amounts of cursing. Pushing out the old bushing, and putting
in the new one will require access to a hydraulic press and a piece of aluminum solid
round to use as a drift. Don't be tempted to use a hammer to do this (you've been warned).