How often is everyone rebuilding their diff?

AaronR · #1 09-04-2007

After 4 race nights (3 runs each... 2 qualifiers and 1 main) or 12 5-minute runs, my (rear especially) diffs sounded very gritty when spinning them by hand. No serious noise (like a chirp while landing after jumps) while on track either which I thought was weird too. I rebuilt (regreased basically, used same diff balls and rings as I saw no wear, just not much grease left) both diffs yesterday and they are much quieter but still seem gritty. I'm using Tamiya Ball Diff Grease which seems thinner than AE grease from what I remember. I can go 10-12, maybe more race nights in my B4.

My track is indoor off-road, hard packed moist dirt (no real dusty areas), so it is a fairly clean environment.

Any tips, comments, suggestions?

bender · #2 09-04-2007

The 501x only comes with standard diff balls so a set of carbide or ceramic jobs will make it feel smoother.

Other things to try is make sure you run dust covers on the diffs (might not be a big problem on your track) and don't use silicone lube for the small thrust bearing (I use the anti-wear grease).

On my diff I put all the balls in the inside ring of holes on the pulley, instead of the outside ring - this made the diff feel better for longer because it made it harder for dust and debris to get between the rings and balls.

DCM · #3 09-04-2007

the downside of using the inner ring of diff balls, it takes more pressure to generate the same diff action, so you can, in exceptional circumstances, shear the head off the diff bolt.

On my Tamiya Touring cars, I use the stock Tamiya Anti-wear grease on the thrust balls, but flush it out thoroughly first, and AE white grease on the diff balls. And diff wear will come from the plates and not the balls, I would guess trying Yokomo diff plates as a test to see if they fir the stock outdrives.

bigred5765 · #4 09-04-2007

in our xxxcr the diff hasnt needed rebuilding in the past 6 months it still perfect, xx4 more like 3-4 months

TRF_Tastic · #5 09-04-2007

I ran the regional yesterday with new diff balls (ceramic Kanzen ones) and plates, and its fine now, now problems and all seem smooth as when I built them.

AaronR · #6 09-04-2007

Sounds like my balls, er, the 501 diff balls are not perfectly round and that may cause the gritty sound and feel? I'll have to get some of those Kanzen ceramic balls you are talking about. I wonder if they still offer free shipping? http://www.oople.com/forums/showthread.php?p=28400

EDIT: Looks like the Tamiya diff shield is this? ... http://www.tamiyausa.com/product/ite...oduct-id=53970