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I picked up a t4 roller with a ball diff.
I have not used it in my 4.1 yet, but hanging on to it for a spare. I am not used to ball diffs. Mine feels like it is adjusted to tight. When i spin one side it feels, not gritty but just not smooth like gears do. Is that normal?

I think I would pull it apart, and check it out just to for my own piece of mind. Sounds like it needs cleaned up and/or re-lubed. Check the diff rings for wear. I just did that with one I picked up not too long ago except it was gritty even after all that so I ordered up some replacement parts and did a full rebuild. Much better now. I also ordered the ceramic diff bearings from Acer. Wow! $1.00 a ball but I've never felt anything smoother.

thanks, i will pull it down. I did not think it was suppose to feel like it did..

a good diff is basically a diff you can't "feel" and that doesnt' slip... there should be no "granular" feeling whatsoever, and when you hold the spur and "launch" one wheel by hand, the other one should spin the other way for about 3-4 turns. Usually a slightly gritty diff comes from shot thrust washers, unless the main ball/plates are really really done! The b4 diff is a marvel by the way, if built properly and if the slipper is set right it can easily last several dozen packs before a rebuild. Best diff in the business!

Paul

Pretty much anytime I purchase a car, no matter what the diff feels like I usually like to tear them apart and go through them for my own piece of mind. either way though they will always have a different feeling than a gear mesh would be, it should just be a smooth feeling. One trick I like to do is take a piece of 800-1000 grit sandpaper and put it on a flat surface, and smooth out the face of the diff rings in a crosshatch pattern. tThis will cut down any high/low spots on the rings, and help make for a super smooth diff. Not to toot my own horn but I have built some pretty butter diffs, it was amazing how much of a difference it made back in my 12th scale days.

well, while the family is watching TV tonight, i guess i know what i will be doing LOL

thanks