Can some one explain how you get a t56 tranny to fit in a 99 gmc 4.8 ????

well tonight really sucked i was about to go for a swim and bang my tranny started to make some crazy noise sounded like blowing thu a peice of grass my tranny started to act up no reverse it would go in to second then skip third and go to od ?????? ok i know i drive my truck really hard so now i need a tranny i really kinda wanted to to break it anyways because i want a 5 or 6 speed can any one tell me if a t56 will fit in my truck or what i could put in it to make it go like snot i have 99 gmc sierra 2wd base model iv done a lot to it 4.56 rearend alburn posi its flash tuned with 3rd stage afi air intake and some other bolt ons some one please help

It's been done multiple times, there is a great write-up on pt.net annd there is an even better one here. Use the search button

so based on your post i assume its a 4.8 auto. it will work but ive heard removing all the auto parts sucks to convert it. if it were a 4.8 5speed to begin with itd be pretty simple. i know the t-56 will bolt to the LSX motors as long as its off an LS1 motor. i had nelson performance redo my wiring harness to work with the t-56. not sure if the stock tranny mount would work i made a custom crossmember. drive shaft would probably need to be changed. its a lot of work but the t-56 trannys are a lot of fun.

if i remember right, the late 2000 & newer auto crossmember will work. since you've already got the 4.56, that'll be a little less work.

you should also consider carefully what vehicle the t-56 came out of. certain models & certain years have different gearings, and i believe the GTO transmissions used a different starter

This is the T56 swap i did on my truck Keep in mind it was already a manual 5 speed and is an 04. I'm sure alot will be different from your truck to mine, but alot of the basics should be the same.

http://www.ls1truck.com/forums/mecha...t-56-swap.html