94 K1500 with 04 1500 HD drive train

EmanGMC1500 · June 3, 2021

So this is my first big project, I was originally gonna Just put the 6.0 from the 04 GMC I bought into my 94 K1500 but then I was thinking of putting the entire drive train. has anyone done this? If so can I have some tips before I start.

CamGTP · June 3, 2021

The engine/transmission and transfer case would be the easy stuff. Aside from needing to make new drive shafts for the front and rear.

You'll never make the 2500's front diff work on that old 1500 frame unless you want to hack it up and custom make everything. The rear axle isn't really needed, it's huge as well and weights a ton more than your current 10 bolt.

You could sell that 14 bolt rear end and buy a new rear locker for that 10 bolt you have and be far better off.

garagerog · June 4, 2021

Cam you're a lot more knowledgeable than I am about these things but the OP in his title for this thread did state that the 04 was a HD half ton so it's a 1500 to 1500 swap he plans.

CamGTP · June 4, 2021

The 1500HD is a 2500 frame. It's got 8 lug axles and heavy duty suspension. I never understood why GM called it the 1500HD when it was a 2500 truck underneath.

We had a 2004 model year as a shop truck years ago. That 6.0 and 4L80e where tough as nails and got 10mpg all day everyday no matter what.

Edited June 4, 2021 by CamGTP

EmanGMC1500 · June 4, 2021

Thank you very much CamGTP. This is all very helpful information.

Jglew82 · June 4, 2021

I agree with Cam, swap in the engine/trans T-case and leave the diffs. You might be able to find a transfer case with front driveshaft from a 2500 or 3500 GMT400 with the 4L80e trans that would be close to the right fit, but might have to swap yokes and/or U joints, or like he said, get some new ones made.

Edited June 4, 2021 by Jglew82