200-R4 shifting funny/too early? Something different than TCC solenoid?

Hello! I have a 1987 GN with a stock transmission. I'm 99% sure that it is the original transmission with 160kish miles on it - I think it's time to get her rebuilt. However, I want to get your input on things first. I'd hate to get it rebuilt only for it to have the same problem after it's done.

This problem came out of no where - it feels like it's upshifting too early like in a manual transmission car. I did a few searches and a lot of people change out the TCC solenoid. I did that, no change.

I have the Scanmaster G installed in my car. One screen will tell me what gear the transmission is in and tell me if the TCC engages. Whenever the problem presents itself, the "TCC indicator" turns on. When it's running correctly, the "TCC indicator" turns off.

Any ideas? Would/could a rebuild take care of this? I'm prepared to do it, but don't want to waste my money. Plus, there are no GN shops around here. I would be at the mercy of a standard transmission shop. Thank you in advance!!!


Texas, Where are you from
Sounds like something is signalling the TCC to activate . What chip are you running? Might be "seeing" an action that causes it to activate the lock up.