Have a T-MAXX 2.5 with a 3.3 engine and it shifted just fine when I put the motor in but now for some reason it wont shift to 2nd gear and runs at really high rpm's. Have it tuned perfectly and have put in a new 2nd gear drive hub and set the shift point as low as possible and flipped the drive hub around in both directions to see if I had it in backwards. I even put the whole 1st and 2nd gear assembly in a high speed drill and tested it in reverse and the 2nd gear dog came out and grabbed 2nd gear and it worked fine. It just wont work in the truck!! I just put in a new engine clutch, slipper is tight and the truck gets up to the speed where it should shift but it won't shift!!!! I have taken the trans apart at least 25 times to fix it and still isn't working right!! I am at a stand still and don't know what else to do. Was thinking about getting a 3.3 trans and just junk this old 2.5 tranny. Is it worth it to replace the trans with a 3.3 trans or keep banging my head against the wall with this old 2.5 piece of crap? If I should replace it, will the 3.3 trans drop right in or what?