You can always add more friction modifier if you need it, but you can't take it back out. Start out with 2-3 ounces, then go find a big piece of pavement. Do a series of figure 8s...add more modifier until the posi chattering stops.I have a couple 10 bolt Posi's I'm refilling.
How many bottles of additive do I need and what is the recommended gear oil...80w90?
I'd like to go synthetic if possible.
Thanks.
I couldn't remember if it was 90w140 or 85w140. It's available at Advance or Autozone right along with the lighter weight gear oil.1 bottle is meant for an average size diff. Yours is in that category. Just add the whole bottle. I use Coast Oil Co "Super Duty" gear lube. It's an 85-90 weight oil that's clear red and superior to the standard non-synthetic gear lube. I've never heard of using 140 weight gear oil on any diff as mentioned. :beer:
Well that's what I've seen and used. I thought you were saying strait 140wt.I couldn't remember if it was 90w140 or 85w140. It's available at Advance or Autozone right along with the lighter weight gear oil.
Actually that "myth" is partially true. As seals age they start to harden. If you switch to a synthetic oil, it tends to soften the seals. That can make them leak. Fear not. The seals will eventually expand back to their original size and stop leaking.GM has always spec'd 80W-90 but 75W-90 is perfectly fine to use.
So any talk of synthetic gear oil being no good or causing leaks is myth. Bad seals cause leaks.