Attention: TDR Forum Junkies 
I have a 96 C/C 4x4 AT. Tonight when I left work the transmission wouldn't shift into overdrive or lockup the TC. The only thing significant that happened between this morning and evening was a 30 minute hurricane of a thunderstorm but I don't think it has anything to do with the problem.
I was able to get the transmission to shift three times in the 22 mile drive but had to accelerate to 2500 RPMs in third. When I backed off, it shifted. A moment later the TC locked up. As soon as I decelerated to 50 mph, it unlocked then shifted down. Lather, rinse, repeat times three.
I initially thought it might be a pressure-related problem but the factory manual led me to check the TPS. I adjusted the idle up some, checked linkage length, and got .8 VDC at idle position and 3.05 VDC at WOT--all in spec.
I decided to check codes after that (should have done that first). It threw a P0123 for TPS voltage. Since I did get a funny read of 5.8 VDC at one point during the test I assumed I had crossed the shorting pin through to another terminal on the TPS connector instead of just the center one (assuming 5 VDC reference voltage?). I removed the test pin, cleared the code and then went for a test drive. I couldn't get it to shift even with the high revs this time and when I got back the P0123 code was back.
Since the TPS checked good I'm hesitant to replace it based solely on a code. Has anyone else seen this problem and if so, what was the fix?
I was able to get the transmission to shift three times in the 22 mile drive but had to accelerate to 2500 RPMs in third. When I backed off, it shifted. A moment later the TC locked up. As soon as I decelerated to 50 mph, it unlocked then shifted down. Lather, rinse, repeat times three.
I initially thought it might be a pressure-related problem but the factory manual led me to check the TPS. I adjusted the idle up some, checked linkage length, and got .8 VDC at idle position and 3.05 VDC at WOT--all in spec.
I decided to check codes after that (should have done that first). It threw a P0123 for TPS voltage. Since I did get a funny read of 5.8 VDC at one point during the test I assumed I had crossed the shorting pin through to another terminal on the TPS connector instead of just the center one (assuming 5 VDC reference voltage?). I removed the test pin, cleared the code and then went for a test drive. I couldn't get it to shift even with the high revs this time and when I got back the P0123 code was back.
Since the TPS checked good I'm hesitant to replace it based solely on a code. Has anyone else seen this problem and if so, what was the fix?
