Associated oil should be very close to Schumacher oil, which is what nearly all the team drivers use, so that makes copying setup sheets easier.
I really prefer the Schumacher diff lube (not sure on the part number), I think it's way better than Associated stealth lube which I used for a while. The Associated lube just seemed to thin all the time and it would be smooth for a few runs and then get flung out of the diff
. I've never had that problem with Schue diff lube and my diffs are always great. I have lots of AE black grease though which is why I use that on my thrust bearings and it works well, although I'm sure the Schumacher Moly Axle grease or whatever would probably work better
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