Cody

I have a 4L60E transmission behind my LS1. It is in a non LS vehicle running on a Painless Wiring harness. My problem is that the trans seems to shift randomly, it may start off in 2nd or 1st and then jumps back and forth between 2nd and 3rd. It has only about 5 minutes of driving time on it but the engine has about 30 mins of run time since putting it in. The trans was behind my previous engine and worked fine. I do have a check engine light on but when we hooked a code reader to it it said it was a fan problem.

Any ideas or thoughts?

gofastwclass

iTrader: (2)

First are you SURE you are starting in second? I ask because without power the 4L60E defaults to third, but you would be able to feel that. The vehicle almost doesn't want to move.

The 4L60E transmission shifts by commands from the PCM. Any shifting oddities are likely wiring related or from the calibration in the PCM. Without being able to datalog the engine and transmission plus read and update the calibration you are simply guessing.

I would check all the wiring connections and make sure they are solid and not grounding on something.

I would speak to the person who tuned the PCM for you and see if / what gear ratio or transmission changes they made. For a stock engine, the stock 4L60E transmission settings are pretty decent.

Cody

Could be 3rd it is very sluggish to move. What would be the procedure to test if there is power to the trans. The sheet that came back from the programmer states the trans programming was not changed.

Pop N Wood

iTrader: (1)

Sounds like the trans is just a symptom of something else not being right. Like said above hook up some sort of data logger/OBDII scanner and start looking at all the sensor signals. If you see anything that doesn't look right follow that and see where it leads.

Cody

I went out and got a code scanner today. Hooked it up and it shows no codes for the trans. I climbed under and found that the 2 plugs into the gear elector module were not pushed all the way in. I removed the whole assy. and cleaned and reinstalled it. I did check for voltage at the pin and had 12V at pin "C" the pink wire on the 7 pin plug. I haven't been able to drive it because it now has an injector issue, according to the scanner.

Cody

OK still the same problem. I can shift it manually but it will not do it on its own. I have power (12V) to the pink wire. My scan tool is a centech 60693. It has transmission codes in it but when I scan my computer none show up, like its not even there. The PCM came out of a manual car. I wonder if they did not reprogram it for the automatic? Just a shot in the dark.

Cody

This is the plug with the pink wire. It is the one in the 3rd or C position.

pdsq98gt

If the programming wasn't changed in the pcm and it was a manual trans programmed pcm, that's definitely the problem. Sounds like you need a tune.

Cody

At this point that's my thought even thought it was supposedly reprogrammed for the automatic. I have access to my same vehicle with the same trans that has a known trans issue. The code scanner showed a trans problem on his but not on mine.

ls1nova71

iTrader: (4)

My money's on this. ^^^^^

Cody

I talked to the guy that reprogrammed my ECU today. He said that he did set it up for a automatic but that if I would send it back to him he would redo it for me for no charge. When I got home today I was working on a issue with the mass air flow meter throwing a code. I found there was no power to it so I looked at my painless wiring manual to find that fuse and would you believe it said that one 15amp fuse controls the Oxygen sensors, Break switch and maf sensor. The break switch somehow controls part of the trans (I don't understand how but electronics are not my thing). Again I'm not sure how the two are related but the trans now shifts correctly.

Thanks for the help guys.