2nd Gen in 87

[Td87]

Hey everyone. I've got a 2nd gen 6bt mounted in my 87 1 ton. I'm using the dodge automatic and still gotta find an np205 29 spline. I bought a full donor truck so I wanted to use the dodge pcm, but I can't find any info online with wiring the pcm into my 87. As far as everything else related to the swap I've got it pretty much licked, it's just the wiring side of it that's holding me back. If anyone has ever done this or has any input on how I could go about wiring this, I'd appreciate it very much. Thank you

[ryanroo]

To my knowledge there are no dodge autos that used the 29 spline output definitely not in that era. you will need a 23 spline input. they are a different case than the 29 spline and the two inputs don't cross. 23 splines came in any dodge auto through the 205 years.

for the wiring, i dont thing you need the PCM to communicate with anything other than the inputs from the engine and transmission. from there it will make the call for shifting/lockup and acts as the OEM dodge alternators voltage regulator as well as the timer for the toasters. i dont think you need to do anything to integrate it with the GM harness other than give it a good power source and ground it appropriately. the gm dash can be made to work with the correct senders and the stock gauge harness modified for the new engine.

[Td87]

Ok for some reason I thought I needed to find a 205 case from a 1st gen because it has the right side drop. Cuz I have a 241 case but that's got the left side drop. Is the 23 spline a left side drop?
For the pcm, I took the fuse box out of the dodge so I'll just power and ground that. I still gotta figure out which wires to use out of the gm harness for the shut down solenoid but that shouldn't be too difficult. Thanks for the input

[Dieselwrencher]

Td87, yes you need a transfer case from a 91-93 dodge cummins that was an auto truck which is 23 spline and RH drop. Or use a 241c that came from a gasser of the same era. As for the wiring, you will need to get the wiring schematic for the year truck your donor is and use the required wiring for the engine and trans to work correctly. You don't need the entire dodge wiring harness to do this. If you get me the ESN, engine serial number, from your engine, I can get you a part number and price for the engine wiring from cummins. I'd recommend getting a subscription on eautorepair for the vehicle wiring info. It's $16 per month but you can print out everything you need for your donor.

[Td87]

I actually bought the Haynes manual for the donor truck. It does come with wiring schematics in the back. I'm just unsure of which wires on the gm harness are going to tie into the dodge harness. Other than the ones for the starter.