need4fun2469

I have recently had a new rebuilt trans and yank 4000ss installed in car. Everything was fine until today.

Feels like the car only has drive. It is not starting off in low gear like normal.

reverse works

The torque converter is no longer locking up either.

If anyone has any knowledge about this, send it please.

I could only find threads where 3rd and 4th was lost.

mrvedit

If you only have 3rd gear then the trans is in "limp" mode. Scan for codes, that should tell you why it is in limp mode.
Did you have the PCM tuned for the Yank stall? If not, that is why you are in limp mode - the PCM has detected too much slippage and forced limp mode.

need4fun2469

thank you for your response. Why would it start doing this all of a sudden?

RevGTO

iTrader: (12)

Because the PCM detects slippage due to the difference in engine rpm and vehicle speed. It's common with converters over 3500. When I went from a 3000 stall to 3600 I had the problem. Had to tune out several DTC's to keep it from happening.

Do a search on "limp mode" on this forum and you'll get all the info on the codes to tune out - I can't remember them now.

thunderstruck507

iTrader: (18)

Mine would only do it when it upshifted on a hill and the rpm didn't drop at all, sent it to limp mode.

If it happens you should be able to pull over, turn the key off for 15-20 seconds, then restart the car. You will want to get the codes tuned out though so it doesn't happen.

need4fun2469

took the car to the shop tonight. I should hear something by afternoon, I HOPE.

Ratdaddy60

Either the 3-2 downshift solenoid is bad or the ground wire in the external or internal wiring harness is not making a sufficient ground. Most likely the 3-2 solenoid.

need4fun2469

It worked normal on the way to the shop. Talking to Chuck at flt, he said it needs to be retuned for the tq conv increase.

need4fun2469

the shop said they tested the solenoids, they worked perfectly. The car drove normal for them as well. They also checked the harness and all checked out there too.

mrvedit

As was mentioned, when the PCM detects too much slippage it enters limp mode. Just turning off the engine resets it and it is hard to predict when it will happen again. Best to get it tuned for a high stall converter - the tune will disable a few codes and reduce the sensitivity of the misfire table.

dreww

iTrader: (1)

+1 on this. My car was unturned with a 4k stall when I got it. never went to limp mode but would constantly lockup and unlock on the highway. The misfire table will fix that. Save you some transmission heat and increase gas mileage too.

need4fun2469

thank you all for replying. I am going to schedule to get it tuned.