I have two '94 Z28s. One has 34K miles and the other 37K. Both cars have new pinion seals leaking and both have Mobil1 SYNTHETIC gear oil 80-90. Has anyone else had this problem. I am trying to find the root cause. The yoke surface is clean and unworn where the seal rides. I need to fix both cars. I will change the oil back to GL-5 80-90 as a test. Please give me your input if you have delt with this problem or have ideas of what can cause this leak.

 

ive changed it on my old Z and on my T/A. they always leak and get everything all oily and crap by the torque arm and such. only advice is make sure they are in good shape, not ripped or torn and dont use synthetic, i beleive it is more prone to leaking out.lol. also, get some thicker oil. try 90-140. that should help.

 

Thanks for the reply 69 z28, I drained the synthetic out of both cars and put 85-140 Gear oil in one car and 80-90 Gear oil in the other to see if both cars stop leaking around the pinion. The synthetic obviously lighter weight, less viscus and would seem more likely to get past the pinion seal. Hope this solves the problem. I hate oil leaks, thanks again.