I am doing a V8 swap into a 97 s-series. Ive got a problem, truck backs up fine but in order to move forward you have to rev it to about 1500 rpm. Its like the brakes are on but you can spin them freely when you jack it up. Its a small block carb motor. I hooked up the coolant sensor and a tps, and just left unneeded wires unhooked.

 

and is there a tach input?

Mind you.. still might not work right unless you hook it to a drac like the early 90 vss you need 3 pulses/rv instead of 4

 

The wiring diagram I have does not show a tach input to the ecm. I'm new to here what is a drac?

 

hows the fluid level in the trans ? have you checked it after shifting into all the gears?

 

I'm not sure it cares about rpm but I would think it would. Reverse is purely mechanical, the forward gear shifting is by solenoid.

 

fluid level is right where it needs to be. Its the 4L60E trans, don't know if that helps anyone.