85w-140 for ATV rear diff

[nwjones18]

I've got an 2007 Yamaha Grizzly 350 with a leaking rear axle. This model has a solid axle not a IRS. I've changed the seals once before and now a couple years later its leaking again. Filled with 75w-90 the first time (specs SAE 80wt GL-4) I'm going to replace the seal that's gone bad and was wondering if it would hurt anything to run some GL 4/5 85w-140 I have in it? Have no other use for the stuff. For what its worth I already filled it with some to see if it would help the leak (no joy) and isn't making any weird noises or anything.. only been in a few days though.

 

[nwjones18]

Well I got it apart and remembered something I'd seen when I had it apart the last time.. The axle itself is badly pitted on the surface the seal rides against, so the seal didn't stand a chance. I sanded it some with my little knife sharpener belt sander while rolling the axle and was able to smooth out the pits a lot, but couldn't sand them out completely. We'll see how the new seal fares. I found some more of the 75w-90 supertec laying around so I put that in there. I'm letting it sit overnight with the wheels off to see if there is any leakage tomorrow.