SavageDad

we added a reverse kit, 4wd kit, and a 2 speed kit, and everytime we run it strips the tranny gears. even the local shop cannot figure it out. so were just going to ebay a new tranny.will a 3.3 tranny bolt into a 2.5 tmaxx?

Snook Man

The tranny is failing because you have reverse installed.

 

The only 3.3 tranny that is a direct drop in is the 4909 transmission with reverse. Those are hard to come by as it is a discontinued truck.

The new 3.3(4908/7) has a forward only transmission and the output shaft is 6mm instead of 5mm, you would need new center shaft yokes to fit the 6mm shaft or convert to the 4909 FOC shaft and brake setup to use the stock center shafts.

You could use the new (4908/7) 3.3 transmission and center shafts but you would have to modify the chassis for clearance of the center shafts and brake.

manyhobbies

My Feedback: (9)

What engine is on the t-maxx, any engine bigger than a .21 or so is gonna tear the stock tranny gears up due to power and tourqe.
I had the same issue when I built my conversion t-maxx with .26 engine. The solve all was putting metals gears in the tranny. I have all metal gears except 1st and 2nd, only ever tore up 2nd gear once. I have a extra new set of gears if you would be interested in buying them to install in your tranny, aslong as you have a standard t-maxx tranny they should fit perfect.
I'm not sure how available the gears are these days but I would sell my set for $100obo and that includes both forward and reverse gearing. I don't get on here much these days so sending me a email would get faster response, [email protected] Let me know. Russ

SavageDad

the answer is in the opening post, and why would anything bigger then a .21 tear up the tranny when it was made with a 2.5

snookman why is reverse messing it up?

steed2-inactive

when someone refers to a nitro angine like a .21 its in cubuic inches, where as your 2.5 is 2.5 cubic centimeters, its .15 cubic inches. For example a savage x 4.6 has a 4.6 cc engine, or ..28 ci. A .21 is a big block and you .15 is a small block.

steed2-inactive

something must not be right, if every early traxxas transmission failed ever run "because they had reverse" i think traxxas would have some warranty issue's. While reverse does have some issues, by no means should it strip the gears every run. Allthough it may be easier to just buy a new 3.3 transmission, this is just a thought, if your going to grab a trans, but look into the extended chassis, lower braces and driveshafts. you will be surprised how cheap these parts are off ebay. oh and you will need a new body.

I did the opposite, i converted my 4909 3.3 to extended chassis, and kept the 3.3 optidrive grey transmission, which requires the use of the late revo trans output shaft to run the reverse still with the late brake disc setup.

steed2-inactive

ok so if you get the late 3.3 forward only trans you will need to grab these items to run reverse, also this will make it bolt right in your truck no issues.
5184 output shaft
5395 output gears
5389x shift fork
3982 outputgears shims (4)
5121 outputgears bearings (2)
5396x Input gears
5183 Reverse idler gear.

This will make your trans a reverse style trans, and use the same style output you have right now, keep in mind this tyle also used the opti drive shift control module which you dont need but must not shift to reverse while driving, common sense, or immediate reverse out put gear damage will occur. hope this helps . cheers

Mclovin350z

There must be a bad bearing or clutch inside the trans you have now.

I would get a grey trans, then fit it with a 4909 style brake and 5mm output. You can always sell off the 6mm output that comes with it. I bought a new grey trans for my 4907 on ebay for less than 20 bucks delivered.

Snook Man

SavageDad

i found what it did last night, it stripped my reverse gear. but only stripped the our 1/;3. i was like ***! so i mic'd the shafts distance with gears meshed then mic'd the shafts with them in the bearings in the case, muthereffers made the stupid case so that the gears only mesh together 1/3 the depth they should.

theres why they fail boys, genius design works

Snook Man

I’ve modified that transmission every way possible, there’s nothing wrong with the distance/lash between the shaft’s and the gears. It is just the nature of the beast when reverse is installed.

bubbafien2

Sorry to be slightly off topic, but this is still relevent...

Is it possible to run the old 5mm output shaft in the new E- maxx transmission? The reason I ask is I am helping a good friend build an emaxx out of my old tmaxx parts. We are using tmaxx 2.5 drive shafts, and differentials. We want to use the new transmission, but I am afraid it is not compatible with the old diffs? The old diff's have a 5mm output shaft and the out put shaft off of the tranny is 6mm. Is this correct?

Any input or suggestons would be great