Ok build is kinda slow now because my emaxx dual motor tranny is coming from Florida shoulda been here wednesday but shipped wednesday due to bad weather. It should be here tomorow so ill mount it in tomorrow and test ut with a single Titan twelve turn to make sure drivetrain is fine. Oh btw my brother pissed me off because he found a $100 brand new tmaxx converted electric with losi controller and associated mgt tires. Though it is powered by a single Titan 12t which gets hot after each run as we expected but it does move the 10lb truck decently on my shorty lipo. He is getting brushless for Christmas . After i mount the tranny mine will be done except for motor and esc which im gettin for Christmas. Then this build will be done and ill move on to a solid axle mud truck. But i will update this thread on how the motor does and what breaks.

nice so far. I built one 3-4 years ago based on the 2.5 chassis. I used a tmaxx tranny with forward only conversion and robinson racing gears. I used a 1/8 tacon motor and ran it on 4s. If you need any pointers or run into problems ill try to help.

Yah well this thing was used hard when my brother bought it for $60 then he gave it to me for 2 2200mah Nimh batteries because he didnt want it. If i drilled bigger holes in the Trans gears they could almost be plastic bushings. Yet the diffs have no wear at all lol. It woulda costed more for new gears and the forward only kit and a new slipper and spur than i got the emaxx tranny for. Btw i lucked out they run $65-85 and i found this one new for $48. I kinda find more fun in custom work on rc cars than driving them except my pede i love it even tho it is still brushed. I'll prolly use this maxx a lot tho because it is my first big scale 4s rc car. And also i prefer owning more rc cars over owning a couple really expensive ones. Next is a wheely king that I'll put traxxas 2.8 talons on lower it a little for mud bogging. Maybe when my 12 year old brother isnt looking ill steal his 4 screw diffs lol

Ok i believe i've said it but i may ask stupid easy to answer questions because i have no time really to find the answer and here is two. First what is the internal gear ratio of the brushed emaxx tranny. Second not so dumb is since i need spur and pinion for tranny what gearing to start would you guys recommend on a 2100kv motor running 4s.

I have a brushless tmaxx on the original narrow maxx platform. I'm running 4s on a 1950kv and I'm using 19/72 gearing. It's conservative gearing but I'm not trying to set land speed records because it's kinda top heavy. It's fun though

Well there's the original 3906 Emaxx with the trans that will bolt directly into your chassis and then there's the 3905 Emaxx that has the same trans as the brushless 3903 and 3908 models. The 3906 is 1.72:1 in 2nd gear while the 3903/5/8 trans is 1.83:1, which do you have?

I have the 3905 dual motor tranny
Can you give me a speed estimate on it Brandon. Post pics if you want

I'd go with a 65T spur and start out with a 21t pinion and see how it goes from there. The 21/65 combo will be right around 40mph depending on your tire diameter.

If I had to guess, I'd say about 20-25 at best with my gearing. But it's a torque monster. I just finished getting my suspension dialed in a couple days ago and haven't had a chance to run it again with the tighter suspension.

I had an overly excessive amount of roll with the red springs. I put progressive springs all the way around and ran it around the living room. it's a lot more stable. Now I'm waiting on a nice day to take it out and open it up. I'm still planning on putting a 3.3 suspension on it for the 16.4" width. Right now it's 14.5" wide and I have the original 5.75" diameter tires on it.

Brandon have you ever tried mounting the battery under the motor or does it not fit beacause that is a high center of gravity

Also the motor fits great in the dual motor tranny

Doesn't fit. My esc is on the other side of the motor. I've thought about building a case to mount them underneath

And it appears that the shocks are in the way of mounting the motor lower to the side is that correct

There would be about 1/8" of room between the shock and motor, but it's a 1950kv motor. A 2200kv or 2650kv would fit better because they're not as long. I used the tall motor mount from how2rc because I was gonna put my esc underneath the motor but it doesn't fit

From what I can find the HPI Scream 1950kv is actually 4065 (40mm diameter 65mm long) while a Castle 1515 2200kv is 4275 while the Castle 1512 2650kv is 4268.

In the TMaxx conversion thread there's a UE supermaxx someone converted. They put the esc on top of the trans, motor in the same position as the stock engine and the batteries on either side of the trans. It all managed to fit under a narrow Proline 1950 Chevy truck body too. I like your ide of putting the batteries under the chassis though. You could make a Lexan skidplate big enough to hold the batteries and bolts to where a center skid would on the chassis braces. I did something like that for dual receiver packs on one of my old Maxx trucks.