jdalaska

have a classic tmaxx i want to change over to a brushless electric & i would like to put the motor on the side of the trany,looking for any help i can get on how to & the best parts thanks for the help.

Maxximize

Is it a stock T Maxx? If so, it will require quite a bit of modification to handle that kind of power. You will need to upgrade the entire drive line including the diffs, drive shafts, and the tranny too. It will need to be locked into second gear, or you would need to convert it to one speed. You will also need to remove the reverse from it with a forward only kit. Traxxas makes a single speed conversion for the T Maxx and a forward only kit as well. With that the black tranny would likely hold up just fine. As far as the motor mounts, the only ones I've seen are the ones that mount the motor where the original engine was, or along side the tranny where the battery box normally goes. Here is one that mounts where the engine goes http://www.ebay.com/itm/Low-Motor-Mo...23752993&rt=nc. There are several different ones that can be found on Ebay so you can choose the one that you like most. Personally, I'd like the idea of putting the motor in the engine mounting spot and putting the ESC in the fuel tank spot. All you'd need for that is some servo tape. With that pattern you'd have room to mount the batteries along the side of the tranny where the pipe and battery box were.

jdalaska

thank you for the input, already went & picked up the steel axels & drive lines, i have a couple more questions to throw at you, is the tranny the same in the first 1,5 t maxx as the 2,5 t maxx i need to know for ordeing the right parts,one more for you what 8scale &10scale motor & esc combos would you suggest, thank you much for your time &input,

Maxximize

No prob, always happy to help Yes both versions of the 4910 (Pro .15 and 2.5) transmissions are the same and parts will interchange between them. The forward only kit number is TRA 4994X and the single speed kit is TRA 5193X. Another worthy upgrade if you haven't done it yet is the torque control slipper upgrade. It converts the old style peg slipper to the newer style pad set up, number TRA 5351X. I've used that upgrade on my old school Maxx years ago and it is a lot nicer and stronger than the old style set up. Oh and don't forget your differentials, too. If you have the old 2 screw diffs they will probably not last long with that kind of power increase. The main difference is the new ones have 4 screws holding the diff halves together where the old diff had just 2 and was prone to flexing under power. You would have to upgrade the diffs to the newer 4 screw diffs from the 2.5 Maxx or preferably the 3.3 T Maxx or brushless E Maxx diffs. The 3.3 and E Maxx diffs will require some heavy shimming and a different pinion shaft to fit with 2.5 and .15 T Maxx center shafts, but they do fit. I just did this mod using brushless E MAxx diffs to my big block T Maxx which uses an older style shaft and a dogbone, so I can share some pics and stuff to help you out if you go that route.

As far as the motor recommendations go, that is where I fall short. I have been out of electric for years now so I don't have enough knowledge to recommend a nice set up there. If I personally were doing this project I'd look for a combo that people commonly use for the E Maxx like a drop in upgrade and go that route. You could always get the stock brushless E Maxx motor and ESC, too. Unfortunately I only really know how to make the T Maxx bulletproof, so that's about the best I can do for ya. Hopefully an electric guy can chime in on that.

jdalaska

thanks for the good info.i'm positive i will have a few more questions for you. i will be in touch & keep you up on how it is going & if you have any more info to share please do.thanks alot jd.

Maxximize

Any time Yea I'd like to see how it turns out for sure. I think it's cooler than an E Maxx to have a T Maxx converted. I've got a few pics of the diff mods I did to my truck for you. It took some hunting and head scratching to figure out so I hope this gets around for those who want to do this in the future. I am using an extended chassis for my big block engine, it's extended in the rear and uses a custom length dogbone for the center rear shaft. The front one is a stock 4910 length shaft as the chassis is shorter in the front than the 3.3 4907/4908 T Maxx is though the overall length is the same. The issue with trying to use E Maxx or 3.3 T Maxx diffs with the older shafts is in the pinion shaft on the diff. It is shorter than the 4910 Maxx shaft is. If you're using stock plastic center shafts you can dremel the ends of them so the pin hole in them aligns with the hole in the pinion if that makes sense. What I did was use pinions for a 4909 short chassis T Maxx to make them longer so I could use my dogbone and unmodified stock center front shaft. They fit in there and use the same tooth count, but the diff case on the input side was shorter than the stock old diff was, so I had to shim it between the center shaft and the diff so it didn't have any slop. Now the stock 2.5 Maxx diffs they make now are 4 screw, but they are not sealed so you can't use diff fluid to tune the diffs. That is a dis advantage for higher power applications as you will get power unload to one wheel under heavy throttle. The 2.5 diffs will drop in with no mods to the truck, though and are stronger than the old 4910 diffs were due to the extra screws. The 3.3 Maxx diffs are sealed allowing the use of diff fluid, other than that they are basically the same internally as the 2.5 ones are but with the sorter pinion shaft. The Brushless E Maxx diffs are the same as the 3.3 diffs, except they have an I brace and steel guid pins inside the diff cup to hold the gears in place better under power. With proper shimming these are pretty strong, and are the strongest drop in diff for Maxx trucks. I went with 3908 Brushless diffs for my truck. They are the most expensive, followed by the 3.3 T Maxx diffs and then the 2.5 T Maxx diffs which are cheapest. I bought mine from a reputable seller on Ebay, lumidave35, that removes them from RTR trucks and sells them ready to go. I think they cost me about $65 for both as a pair.

Now, to make them work with my older style center shafts, I had to get a different pinion shaft. I used 4909 T Maxx pinion shafts for this, they are the same length as the older style Maxx shafts were so they line up well with the pin holes in my drive cup and cvd end. The part number for the 4909 shaft is TRA 4981, it comes with the shaft and a ring gear and cup and some hardware, but all you'll need for now is the pinion shaft. The rest is spare parts. After that, the shims are needed. I ended up using some 6x8x.2mm diff shims, and some larger and thicker 6mm washers from the hardware store. The thinner shims are for internal shimming if it's needed (Mine needed no shims, but some will need them), and the thicker ones are used with some thin ones for external shimming. With all the washers installed my diffs were nice and solid with no play at all in the pinion shaft, which is ideal. All said and done, the diff upgrade cost me about $95 for all the parts required and the diffs. I also bought some automotive bearing grease to lube the ring gear a little bit more when I had to take the diff apart for the new pinion shaft. Grease is used on that part, and silicone diff fluid is used inside the cup, which is the sealed part. You will not need to touch the cup at all at this time until you want to try different fluid weights. Many people like really thick fluid for brushless it seems, stock is 30k. Anyways, here's some pics of the diffs.

Here are the pinion shafts, the left is the 4909 T Maxx shaft and the left is the 3908 E Maxx shaft.


Here are the diffs, the left one is the original 4910 Pro.15 diff with the 3908 diff on the right with the 4909 pinion shaft installed. Note the difference in the length of the diff case behind the pinion shaft. Make sure to check the rotation of the diffs before installing them, they will work front or rear, but need to be flipped opposite of each other so they turn the same direction. Here you can also see the extra 2 screws holding the diff case together on the pinion side of the 3908 diff. The old diffs rely on the collar to hold the pinion side together, and that is their weakness. The plus marked on the old one was done so I knew which side had to face up when taking them off and reinstalling them. I also mark them front and rear.


The 6mm hardware store washers I used showing the thickness of them.


The 3908 diff with the washers and shims installed with my drive cup. I used the smaller 6x8x.2mm shims on the bearing side (2 of them I think) and the thicker wahsers on the drive cup side so they don't contact the outer edge of the bearing. The output cups required no shims and fit perfectly.


And the finished product in the truck. The dogbone is sitting just right in the cup with just enough play so it won't fall out but won't bind as well. The front stock plastic one required one less thick washer than the dogbone did.