Quote:
Originally posted by IPM
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No problem.
Ohh one other thing I ment to tell you. 90 or 91 is when they started running the 4l80. The ECU on those models drove both the FI and the transmission. Before that it was the the TH400 or TH475. The ECM is going to have to be reprogramed for sure if the truck had a 4L80. It will throw codes and might even kick into limp mode Thinking it had a transmission failure. If the doaner had the TH400 you might actully get away with out programming. Hard call till you get it on there and see how it reacts to the cam.
TH400 has electric kick down. On your MH there will be a trigger switch on the throttle. Most likely right at the peddle. On a FI set up that switch is not there. It's triggered by the ECM. You could leave it as is or you could tie it into the ECM. The gain to tieing into the ECM would be if the ECM sees the engine coming under load at a lower throttle input it will down shift the transmission earlier on it's own.
On my burb at lower speeds like around 40 it will down shift out of 3rd at half throttle with not much more delay then if I had gone full throttle for passing gear.
I had inadvertently knocked the wire off the tranny and it would not do the same thing without that input on the modulator alone. In fact once it was in 3rd it would stay there untill I stopped. With the ecm it will actully down shift on deceleraton out of 3 down to second at about 20-25 mph. So it's a pretty nice feature that I personnally would hook up if possible. Should be able to tie into the stock relay but the TH400 doaner you will find a pair of relays allready on the harness. One is the TH400 kick down and the second is the fuel pump relay. They mount on the fire wall to the left of the distributor (as facing engine in truck).