Got an odd question. I'm running an 86 AUM on a basically stock engine. I have a 4th gear switch in the trans (2004r) and I have it wired to the ECM.

Now the 86 does not use the 4th gear switch. What are the implications of running one when the ECM doesn't use it?

The reason I ask is because I have some goofy TCC stuff going on that can't be explained by normal means. All readings are good and steady but the ECM likes to lock and unlock the TCC too much.

I would think that it shouldn't matter but you never know. Just wondered if anyone had run into this. The only thing I'm left with diagnosis wise is a bad ECM.

Going to go to an 89 bin when I get this figured out then the mods/new engine begin. Then once that's settled I'm probably going to SD on it.


I'll pull the switch wire out of the TCC connector and just see if anything is different. I always end up with goofy problems that end up like that. Maybe something in the GM programming doesn't like it. Wouldn't surprise me.