GRIMREAPER

iTrader: (13)

I have a tmaxx 2.5 stock. I'm thinking about going brushless. I seen the motor mount kit. I'd like to know if the stock 2 5 trans and diff will hold a 1/8 brushless setup. I'd like to have a 2 speed trans. Would the 3.3 trans hold up better

Overdriven

iTrader: (18)

There's a thread or 2 on the subject and from what I've read neither trans holds up well to 1/8 brushless especially as a 2 speed. Converted to forward only with some metal parts to convert to a single speed seems to be the answer there. The diffs will hold up to a surprising amount of power when shimmed properly with metal shims (instead of those Teflon washers) and aluminum outer diff cases. That's the inexpensive way, updating to 3903/5/8 diffs cost a little more but can end up more durable. Stock, the 2.5 diffs aren't really up for 1/8 brushless power and neither are the stock driveshafts. Updating to 3.3/brushless spec Traxxas sliders requires changing the knuckles too so there's quite a bit involved.

If you're ok with a 4 pole 1/10th system, then you can run the 2 speed leave the truck mostly stock and have it live.

Upbasher

iTrader: (3)

The 3908/2905/3903 diffs are different. The 3908 version has steel beams in between the gears for extra strength

GRIMREAPER

iTrader: (13)

Thanks for the info I'm going to pass on this project I see it becoming a mobey fast lol

Cummins Driver

iTrader: (19)

I think If i were going to do it, I would go with a 1/10 brushless system on 3s. It would be plenty fast, especially if you kept the 2 speed, and wouldnt break nearly as much. You will have to redo the whole truck if you go with a 4s 1/8 scale setup. lol

Overdriven

iTrader: (18)

Incorrect. The 3903, 3905 and 3908 all have the steel beams and the rest of the drivetrain is also identical between all three. Early 3.3 Tmaxx's (non extended chassis) didn't have the steel beam but were sealed diffs and had 4 bolt outer diff cases. Something you had to watch out for when buying from a chop shop as they'd often pass them off as 3903/5/8 diffs. Pretty sure the new extended chassis 3.3 tmaxx has always had the steel beam.

Also of note is the Revo 2.5 and 3.3 also never had the steel beam at first either. The ERBE however always had the steel beam as brushless power is what prompted the diff redesign in the first place.

humayraykinaon

iTrader: (4)

non of the traxxas nitro have I bar in there diffs.

spookie

iTrader: (25)

Negative. It has the two spider bars, but not the I Beam. I researched all of them before I upgraded mine to 3908. But their still stronger than the 4910 diffs. I just gave away a 3906 I upgraded to mostly brushless, do yourself a favor, buy a BL roller lol.

Overdriven

iTrader: (18)

You're right. I forgot they made that in between version for the nitros with the inserts (spider bars) but without the steel beam/I bar thing that the brushless ones have.

spookie

iTrader: (25)

I have a spare 3.3 dif, I assume I could just add the I Beam to it and have a 3908 dif? That would save me a few bucks, 3908 difs are little pricey.

This bar http://www.ebay.com/itm/Traxxas-5382...item43c1aef958

humayraykinaon

iTrader: (4)

you need this also to go along with it http://www.ebay.com/itm/Traxxas-Diff...item27da0f1359

palmermax

Hi folks. First time on here. Nice forum. Just wondering about something as I'm doing similar conversion. Not much cash so converting old 1.5 tmaxx 4910. Doing forward only and reverse removal. What did you folks do with the brake? Just leave in place and remove servo link? Or is there a way to easily take the disk out too? Haven't got to that bit yet :-) thank you.

spookie

iTrader: (25)

Ah thanks. I stand corrected, last night I looked again on the Traxxas Exploded views and the 3.3 T-Maxx doesn't have the twin slide in support things. So it would still be cheaper to get the part above and the I Beam below and build it yourself.

http://www.ebay.com/itm/Traxxas-5382...item43c1aef958

humayraykinaon

iTrader: (4)

(4910 black tranny) if you can get the single speed conversion then your motor do the brake/reverse for you, other than that you can also do the 2nd gear lock mod (check out youtube vids on how to)

palmermax

Thank you. Yes have single speed mod. Was just thinking of how to tidy up by removing brake pad.