Seen online in a few places, some people have figured out manual swaps in various GMT900s. I’ve seen a T56 swapped Sierra, and a Yukon with an unknown manual in it. Nobody seems to give any details about the tuning involved. Most forum posts I see about this swap are pretty old, and the main concern seems to be getting the BCMs to play nice with not having a TCM signal. Anyone have any info on how this is being pulled off? Or at the very least know what BCMs are affected and if it’s something that can be worked around.

 

You need a tune from a manual truck. I believe they were only sold in Mexico. They got the GMT900 with a manual in it.

https://www.performancetrucks.net/fo...mexico-462857/

 

Wonder how hard those tunes are to track down. I’m not too necessarily worried about making the rest of it work, but sounds like that’s something I’ll have to track down before I start ordering parts

 

You should be able to buy a stock tune from a tuner or find one in a tune library.

 

The computer needs to be flashed with a GM tool, HP Tuners is not able to flash all 8 segments required for a swap like that. Even if you found a tune to try and write entire with, it will only do 6 of the 8 segments needed.

A few guys on HP Tuners are might be able to help you out. Some have the GM Tool that can flash a PCM with the write calibration file. Might be worth posting a thread in the GEN 4 V8 section asking is someone can help with a NON US tune file flashing.

 

As for a manual Tune, You just need to find a Vin number from one of those trucks and then it can be flashed in with GM Tool and GM programing as mentioned above.

 

I appreciate the advice, sounds like the homework of finding somebody to do it will be a bit difficult. I’m still very early in planning things out, as it’ll be my first build and I’d like to have things put together as quickly as possible. Hoping by sometime next year to have parts ordered and the engine assembled and ready to drop in.