When you grab your truck before youve run it and turn one wheel it usually has alot of resistance when you spin it and let let go it stops right away from the diff fluid. Now i notice when i run my truck for lil bit and i spin the wheel it spjns much easier with less resistance. Is that normal? Does the diff fluid heat up after use and become less resistant?
The diff should hardly get warm. Then again maybe it does, but that's what grease is for, to lubricate which reduces friction which in turn reduces heat.
What weight fluid are you using? How do you run your truck when this happens? Does it become more resistant again after leaving it sit for a while, in other words is this a repetitive thing that happens every run?
Summit; Spartan; Others yet to come
The fluid will heat up slightly with use. All the moving parts no matter what if they are covered in grease or sealed in fluid will generate heat. As the fluid and grease get warm they get thinner and things move more freely
I use jb weld in my diffs. Before a run the tires are hard to turn and during the run they spin much easier. But i quess its normal for a diff to become more relaxed over time.