Big Heavy Aluminum Emaxx Needs Bl Motor Sytem Recomendations

This is a good start -

http://monster.traxxas.com/showthrea...+Diff+Shim+mod

I use A&E Black grease or 1:1 wheel brg grease, thicker the better, helps diff action. As far as shimiming goes, the last set I built I tried the above, but found the teflon washers (.020" thk) caused the diff assembly to bind, so I didn't use the extras, only the stock one thats called for. He demo'ed the mod using a stock plastic diff cup cup and I used a flm alum cup (which came with shims). I had no endplay with my assembled diff.

Mine needed shims though to make diff assembly fit in diff cases right and provide proper R&P mesh. It takes a while and you need to understand what adding shims on one side or the other does - you are basically moving ring gear back and forth in the diff case, setting depth of engagement of pinion. I get the side to side end play of the diff pretty much shimmed out and then look at how thick all shims total up to.

I start with them split between right and left cases (1/2 of thickness on each side and trial fit the pinion. Don't get impatient and dont put grease in until you're absolutely finished. This may take 20min and more than an hour. I get mine until they are slightly tight or snug feeling and there is usually at least a rought spot or two. This disappears when the spyders run in against each other and has always disappeared by the end of breakin. The GA cases only needed shim under ring gear side, but it was def needed. I built a set using gpm cases and they needed shims on both sides and more than one. When you are testing the fit, tighten everything up just like you would on final assembly and see how it feels. Since you've set the endplay in teh diff, you're only paying attention to how it feels to turn the pinion and what endplay there is to the pinion.

One way to learn is to add enough shims to lock everything together in the diff cases and then take shims out one at a time until you're nearly there - now it really matters how many you have on one side or the other. Once you've got this part right, shimming the pinion goes pretty quickly(sets how far in or out the pinion goes on ring gear). You'll be much faster with second diff than your first. Its sounds complicated, but its not that bad once you understand what you're trying to do. The pics from the link should help.

I've never fooled with a spool, so can't help there.