chevy truck drivetrain swap, questions....

[beachbum29]

ok.. here goes... i'm taking my 84 gmc 1/2 ton 4x4 plow truck apart.. I picked up a 1991 3/4 ton 2 wheel drive surburban for parts, mostly the tbi engine, and various assorted other parts.. I'm in the middle of painting the nose, and doors for use on my truck, I cut off the rockers and will fry them onto my truck, took the captain chairs, console, headliner, overhead console, dash, and complete harness for my truck with the pw, pl's etc..

well, I screwd up and did a brain **** on this deal as while i'm taking apart the burb, I found that the speedo is computer controlled instead of cable driven.. Now, my dilema... how much control does this computer in this burb have? I don't have the funds to swap my 700r4 tranny in my truck to the correct computer controlled speedo one, so I was going to just put my 84's cluster back in with the speedo cable, however that would leave me with no check engine light in case something screws up.. will this work? will this effect the way the engine runs at all? would I be able to trace out the harness, and maybe give it a light of some sort in place of the stock in dash engine light? I'm also nixing the ABS that the burb has and not using it in my truck as I really don't care for the early 90's abs setup. I believe this can be bypassed without any issues, or am I mistaken?

ok, now, I haven't looked, but will the speedo seperate from the burb's cluster, and allow me to set my 84's speedo in it's place, as this would allow me to keep the service engine light, and my cable driven speedo?? would this fly? (dependant on if the computer will run the engine without the speedo sensor sending in data).. is there another solution that I may not be aware of?

yes, I'm also using the oil cooler, and ps cooler as this is a work truck, if it's moving, it's working....

Thanks for any input..

Mike

[mrjohnwayne]

If you are taking the whole wire harness from the burb, then you should be able to just take the reluctor gear off the tail shaft of the 700 along with the speed sensor and put them in place of the old gear assemblies in your tranny. I think it'll also work if you have a th350.

[beachbum29]

well, as I've recently found out by talking to a very informative source.. in order to do this swap the correct way, I'll need to either

A: change out the transfer case to a 1990/1991 transfer with the electronic speedo output..

B: swap in a 1987/1988/1989 dash computer harness, and cluster gear which will allow me to run the computer, and give me mechanical speedo control...

Just thought I'd post the results of this problem, and answer I found....
Thanks for your help....

Mike

[mrjohnwayne]

my bad. Wasn't paying attention in your first post. Did not see that it is 4x4.