Originally Posted by Slowcrash_101

The best brand is the cheapest easiest to get brand, they'll all work as long as you use the proper viscocity. Our torsen diffs will give a little bit more locking with a more viscous fluid. 75w-110 is the best compromise of all weather and heavy use protection. 75w-140 may "cushion" parts a little better, but the extra locking from the diff may offset any wear benefits. I've never had a problem with Honda MTF in the box, I change diff fluid yearly and transmission bi yearly.

Originally Posted by Slowcrash_101

Normal means some fine paste on the plug. It can look like shavings because of the field lines in the plug magnet, especially if you don't bother cleaning the plug for a few years. But if you're pulling the plug and there's chunks you can't smear between your fingers I'd start to pay attention.

Use straight 90 weight gl5 gear oil, or 75w-110 or 140 or an 80w 90. There's plenty of good fluids out there. Pick one and stick to it, jumping from fluid to fluid can have consequences. Not too common but I've seen a diff or two give out after switching to amsoil from LE1605. Not in anyway to badmouth amsoil, they make great products and probably won't cause issue as long as you stick to using only amsoil.

So I just stick to Mobil 75w-140 because it's cheap, easily available, and worked for the last 3 years.