Hey everyone, I am trying to develop another transmission setup for the s2000 (after my 350z trans setup turned out louder than I would like). I found a potential doner transmission from the 05-08 Dodge Dakota / 1500 trucks. It's a 6 speed Getrag unit, model 238 and is rated for 520 Nm or 383 ft lbs torque. I've already disassembled the transmission and taken the vital measurements, and so far it looks to be a good candidate. My biggest concern however, is whether or not it will shift smoothly at 8-9k? I've read about stock t56 boxes and BMW units being taken that high even though the doner cars didn't rev so high. My question is what are the main differences between a "low revving" transmission and a "high revving" one? What happens if it "doesn't shift into gear" at say, 9000 rpm? Just trying to see if it's even worth it to move forward with this transmission, or if I should sell it off and pick up an M3 gear box... Any help is much appreciated, thanks in advance!

 

It all comes down to how the gears are cut as well as how the synchros are designed/what material they're made out of. Some research on these topics regarding that specific transmission would be a good starting point.

 

Didn't find too much info on the guts. The Getrag website says their gears are made of
16/20 MnCrS5 and 18CrNiMo7-6 steel alloys and hard-finished, helical cut. First and second gears have triple cone synchros, double synchro third and forth, and single cone synchros for fifth and sixth. Aside from the beefier input/ output shafts, the rest of the internals look to be at least as beefy as the 350z guts.

 

I wouldn't count on any truck transmission to shift smoothly 2000-3000 rpm higher than its original max input shaft speed.

 

The syncro material type and the surface area of the actual blocking ring as well as the weight of the actual shafts and the type of fluid used all play a factor. The whole idea is to use a friction brake to speed up and slow down shafts operating at different speeds. So factors that effect friction and mass differences will all be factors. Truck transmissions tend to have relatively large heavy shafts with comparatively small blocking rings and therefore are not ideal for racing. Not to mention truck transmissions usually have undesirable gear ratios as well more suited for towing and not well balanced. I am guessing here that you don't want to use the S2k trans due to power limitations... if that's the case I personally would go with a TR6060 or a V160 both can handle obscene amounts of power and are designed to be raced.