Ongoing Tailshaft Seal Leak (after seal remplacment)

[RAPID]

Hello all,
I recently picked up a very clean 02 Yukon Denali XL. It has the 6.0 and AWD setup. It has 150K but was garage kept and kept immaculate by the prior owner. One issue that keeps coming up is the rear tailshaft seal on the AWD leaks! I have replaced it twice over the last 5K miles and it just continues to leak. I cleaned what little rust was on the yoke and installed a new tailshaft bushing and that did not help. Seeps out while driving and leaves a small drip spot on my driveway. One shop suggested that my driveshaft may be out of balance and to replace it (not sure how that would make it leak). Another shop said to install a new nickel plated yoke and that may eliminate the leak. There is no clunking or excessive play but I need to figure this out as I drive 2500 miles round trip twice a month and have to keep topping off the transfer case. Any suggestions would be greatly appreciated!

 

[Erickk120]

If it was the driveshaft you would feel the vibration at high or med speeds. Mine was leaking due to that but not as bad as you mention. I would have guessed bushing, but looks like its been replaced. Check to see if there is play in the yoke to transfer case tail shaft. Also not all seals are created equal. I've had to do my front transfer case seal twice, the one thats a two piece. Same went for my rear end. Ended up getting OE seals for my axle shafts also as the aftermarket ones seeped a bit. Been bone dry ever since.