here is the short story got an engine and trans from a 89 Camaro and stuck it in a 89 Firebird.

Firebird= Electric speedo setup
Trans= Mechanical

so I had a trans shop put a vss and a electric speedo gear in the trans. If I plug in the wire to the trans from if I just bearly drive forward the speedo will jump from 1mph to 120 and kill the engine. Doesnt look like some small calibration would fix this one. I'm getting all the sugestions on what to do but I though I would ask around here again. Some say to replace the whole tail shaft, so I might try that, Just pick one up at a junkyard and test it out with the electric speedo gears already in it. If I have the same problem then I probably have some computer problem in that car. Does anyone know anything on this or know of a web site that gives technical information on this topic? Thanx 4 your time in advance

 

why not take it back to the trans shop?