2002 Sierra 4.3 w/ 4L60e trans.

This is my first auto rebuild

I had originally lost 2nd gear and then I lost 4th gear. I rode with 1st and 3rd for a few weeks before I got around to replacing the fluid/filter and shift solenoids only to still have the issue.

I ordered this rebuild kit. Since the research I did on the issue could have been several things (sun shell, sun gear, 2-4 band, servo, ect) I decided to replace everything I could when I was in there.

During the rebuild (and not being a knowlegdable transmission tech) I couldn't seem to see any sign of reason to why I lost 2-4 gears. Well, everything in there looked like it was in excellent shape. No metal in the pan, gears,clutches, seals all looked fairly new (for my first look inside an automatic). I went by the book on the rebuild as well as the installation of the shift kit. Taking my time and double checking every step. (So I thought)

Upon reinstalling the transmission and dumping 10qts in proir to start up, when I did start the truck the motor had a strain on it like it didnt want to stay running. After a minute of running it started to act normal. Then I proceeded to check the fluid and the dip stick was almost full to the top of the tube. The pump was not circulating the fluid (I assumed). I let it run for about 5 minutes longer then I tried to test Reverse and nothing, Drive and nothing, 1st and nothing, ect. I then realized I had broke the rotor in the pump. So I removed the transmission again and yes I broke the rotor:


And the pan after the first removal:


Since I had the transmission out I decided to pull everything back out and inspect it since I had ran it with no circulation of the fluid. Everything seemed to look ok until I found this:


Which is 654c in the skematic in the input clutch housing


So moving along I reassembled everything and reinstalled the transmission for the second time now ain: I started the truck up and it had a slight strain on the engine causing the headlights to dim due to lower RPM's. Well that went away after a minute of running and I checked the fluid and well I got the TC right this time. So backing out the garage I had reverse!! So putting it in drive for the first time I took off real easy. First gear then shifted to second gear (slightly harder shift then before the rebuild/shift kit). Second gear rev'd up to 3K rpm and then it just broke, as in it dropped off like it was in neutral or slipping. It never went to 3rd gear. So once it slipped out of 2nd and it went back to first gear it never would shift back to 2nd gear. Just stayed in first gear. I brought the truck back home and called it a night.

The next morning I went out for another test drive, shifted from 1-2 and then the same thing happened. So I proceed to pull the plug on the harness to run the truck in default. In DRIVE there was no 3rd gear, it was in first gear. Manual shifting I could get 1st and 2nd gear and they function well. At WOT it will still not shift from 1-2 with the harness plugged up.

So I pull a code from the CEL and I get the DTC P0741 which is the TCC. But from the research I have done even with the TCC being faulty (could be several reasons why it tripped the PCM) that should not effect me from shifting into 3rd gear/OD

Right now I have reverse and only when the truck is cold I have 1st and 2nd gear until it warms up then I only have 1st and reverse.

I am giving in and finally posting for some help! I am at a loss on what to do, what to check, and really not looking forward to pulling the transmission back off again Maybe someone with more experience than me can chime in. And help me out.

 

Wow what a project.

I've never undertaken rebuilding a transmission before, so I've got to give you credit for at least trying! That's of no use to your problem, but good luck anyways.

 

Thanks man, I am almost at the point of giving up and putting a used one in it.

I definitely bit off more than I can chew.