Full Size Jeep Network

I have a J3000 that I am planing on doing a frame swap with a Chevy 2500hd. I have a 6.0 Lq4 LS Engine and already have a rebuilt T56 transmission. Will a t56 fit in a J Truck?

There are a couple of YouTube videos about adapting the T-56 to 4WD.
https://www.bing.com/search?q=T56+to+Jeep+transfer+case
You could call the adapter makers, Novak and Advanced, and ask.

Certainly there is plenty of length for a six-speed in a J-truck. If it's a 2500HD frame, your main concern will be how the drive train lines up with the body after you have figured out the mounts and such. Suggest you measure and mock it up, then decide. That's how such things are done, AFAIK.

Physically fitting likely won't be an issue since you are doing a frame swap. Though depending on the year, the GM frames are a bit wonky when it comes to fitting other bodies on them. Though its nothing that is insurmountable. But you will likely have to move the engine front to back so that it clears the cab, while also having the wheel wells line up with the front tires.

The T56 has a rear mounted shifter, so you should be good on dash clearance with the shifter. FSJ's used a 5" spacer between the bell housing and the transmission (When a V8 was used) to move the transmission back so that it cleared the dash.

As tgreese noted, in stock form, all T56's are RWD only. But can be adapted for 4wd.