1988 diesel 1 ton square body

[Dieselbrent]

I installed a 1997 chevy 4L80E transmission and transfer case. I bought a TCU for it and thinking it would bolt up and change gears like its suppose to. Ends up the truck needs a tach so it knows when to change gears. I'm needing help on how to complete my conversion. Or a different route to go. Thank ya.

 

[yevgenievich]

Do not know the exact answer, but from 91 to around 94 gm trucks had 4l80e with diesels running stand alone controllers from factory. Just need to look in to how they were set up.

 

[Blue Ox]

Some of them had a tach signal generator attached to the vacuum pump drive in the rear of the block. But I'm not sure if that makes the kind of signal your controller wants to see.

 

[SquareRoot]

Give it all to me. In return, I'll give you a complete nv4500 setup?

 

[Matt69olds]

Assuming the truck had a automatic trans before, something had to provide the PCM with a tach signal to control the lockup converter and cruise control, among many other things.

Do you have access to a service manual?

 

[yevgenievich]

Cruise was on speedo and lock up on vacuum and gear switch. The 91-94 years should have one of the options that was mentioned above. Or retrofitting crank or cam sensor if outside factory set up. Even just a sensor on one of the pulleys would work

Assuming the truck had a automatic trans before, something had to provide the PCM with a tach signal to control the lockup converter and cruise control, among many other things.

Do you have access to a service manual?

 

[Paladin]

Ahhhhhh.......... the joys of computer controlled components!!!