Our 5.9/Allison conversion in 1997 Suburban 2500

[Dante04SRT]

We're currently working on our latest Cummins swap.

Its in a 1997 Suburban 2500 4x4.

We've got:

1995 5.9 Cummins (P-Pump)
2007 Allison 6 speed auto
NP 263 XHD xfer case

We've got it all bolted up and mounted in the truck and are working out some of the remaining details... the biggest of which being the transmission wiring.

We've spoken to Destroked about their 6 speed controller and they said its not happening anytime soon.

We actually have the wiring harness from the donor truck and have isolated all of the transmission specific wires out of it, along with the trans computer. My boss (the truck's owner) swears that all its going to take is using the isolated wires from the harness along with the trans computer and then giving it some power on the appropriate wires (we've got the trans wiring diagram) and then hooking up things like a TPS to it.

I have searched for hours for information on anyone attempting this swap and have come up empty handed... as far as the trans goes that is.

Has anyone worked with this trans with a swap before? Are we on the right track or is there way more to the wiring (and making it work!) than my boss thinks?

Just curious

 

[1-5-3-6-2-4]

that is the right track. you will just have to feed to tcm what it needs, and you should be gold.

 

[THEFERMANATOR]

The 6 speed TCM for a DURAMAX truck uses CAN BUS to communicate with the ECM for its data. The DESTROKED box uses J1939 data which is what the 5 speed TCM uses. There is NO way to just hook up a TPS to a gen 4 TCM from a DMAX truck as the TCM only looks for throttle percentage on the CAN BUS. As far as I know there isn't any medium duty application either for the 6 speed ALLISON. When I did my swap I was told by EVERY ALLISON dealer I called that EPA laws will not permit them to program a TCM for a truck that is 3500 or smaller, so I doubt you can get ALLISON to make a tune for you. The only way I can think of to get it to work is either call Brayden at Fleece, or get a 6 speed TCM from a 8.1L truck(which is RARE!) and a DESTROKED box along with EFILIVE tuning on teh TCM to bring the shift points down. The 8.1L TCM though still isn't a very good option as 5th and 6th gear will not engage if you give it more than 75% throttle IIRC. Your best option would be a DESTROKED kit and a 5 speed valve body and convert it back to a 5 speed.

I wish you luck in your swap, but I believe you are up against a brick wall here trying to retain the 6 speed.