On to the results.
After I had the the truck towed to my local Chevy dealership they determined that the recently installed speed sensor was bad. They replaced it with a new ( one would hope that they would ) one, put it back on their computer , took it for a good test drive and problem fixed.
So there was no internal on board computer problem. Nothing needed to be recoded. It was just a sensor. The transmissions is in good working order, I will be keeping a watchful eye in it for the next few days. All in all its running like it should.
Next on the fix it list, the transfer case actuator. Power is going to it , the internal motor is just not doing its job. So take the clip off, pull the wire connector, unscrew the actuator and replace with new. Oh the joy of spending money and time on something I just want to run correctly .
hopefully it all corrected.
Frat, all is fixed on the transmission. Like you had highlighted, it is a matter of not just installing the transmission but making sure your wiring is installed correctly. Make sure that the main harness plug is warmed so that it fits all the way into the socket. If buy reading my thread helps you in any way, thats great. My best plan of attack if my trans goes bad ( knock on wood , never again.) I'm taking it to the dealership. My route was a disaster from the beginning . lesson learned . if you are a mechanic then this it is not a problem for you. But if you are just the standard Joe trying to replace the transmission my personal opinion is have a professional do it. It will save you time and money in the long run.
I had stated in the prior posts that the mechanic doing this work appeared to lack the proper equipment , to diagnose your vehicle. I recommended you go to another shop that has the proper test diagnostics.
you defended him with his 20years experience. with out the proper test equipment this is not much help for your issues.
good to see it is all corrected. electrical connections and wiring is a big problem with repairers not properly trained in working these computer controlled vehicles.
I would not recommend anyone to go to the dealership with a vehicle this old however. I have no idea where you live so perhaps you have no choice but go to the dealership for these complicated electrical issues.
You mentioned something here that I wan't aware of being an issue until recently.
"Make sure that the main harness plug is warmed so that it fits all the way into the socket."
What process is used to heat this up without totally torching the thing?
Understood. I had a bad shift solenoid and this week my 2nd gear is gone.
Looks like I'm on the hook for a rebuild, but the $2200 price tag seemed steep. What do you guys think? They said it's in pretty bad shape.
The truck has 165K miles on it. I know the engine will do 300K if I take care of it. Aside from a fair amount of body/chassis rust and a few odds and ends, I'd much rather prefer to fix it and drive it in to the ground than take on a new car payment..
I know this is a pretty old thread but i have a 99 gmc sierra 5.3L 4l60e tranny has 250k miles. Tranny has had a semi hard down shift into first for a while now but it got way worse today. Drove about 5 miles and completely lost all gears (P,R,N,D etc.) along with loud grinding and popping sounds but only in 2wd. i can put it in 4 wheel high and it drives decent, minimal slipping and not really any grinding. Im thinking its the TC but wanted to see what you guys think. A buddy of mine was saying it may be my rear end.