Big Heavy Aluminum Emaxx Needs Bl Motor Sytem Recomendations

Question on your diff prob - are you shimming them? Mine don't last without shimming, but I'm only running an 8XL. I'm running GA alum cases and collar with flm diff cups, but shim mine so they start tight. Seems to work.

The weak link in stock trx diff is the spyders and the RRP stuff doesn't seem to be as good as the stock diff parts, so I'm not surprised about your experieince with RRP. I have a Supermaxx (and a DacePredator) and spent time on UE - known prob over there with RRP diff parts for a Tmaxx.

UE diffs are currently available new but pricey. Used can be found but you have to watch ebay and or the UE BST forum to find them. 8 Spyders are real hard to find used here lately. That is if you need cases and all. If you don't need cases, the 1/8th diffs (6 or 8 spyder) are in stock at UE and aren't geared as high as HB diffs if that makes any difference. There are a few UE lightning based guys on UE and they would tell you only solution to your prob is 8 spyder UE diffs - I know, they've been telling me same thing!

Did the 4-Tec start out as the elec version? Nice work, looks trick!!

I raced a 4-Tec pro for a while and have a 2.5rtr. I want to put a TZ in when I find a big place to run in. I see I am back to 1st post again, was posting in temp forum when I got started here....

[JCUEVAS]

It was a totaly stock electric 4-tec with a mechanical speed control. i shimmed it but honestly don't know if i did it right. The shims go on the inside of the diff cups before the two output shafts right? How should the diff feel? Easy to turn by hand? Should there be a little bit of resisdence before they wear in or smooth from the gecko? What type of lube should i use also? I used a thin layer of the black rr grease. I've seen different types of diif lube. What do you recomend? I really don't want to spend allot on new diffs. Thankyou for your help.

[JCUEVAS]

Should i just throw a spool in the rear and let this thing go?

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.