stromminmn

I have a 2005 Suburban 1500 LT 5.3 with 161,000 miles. Runs drives and shifts real well. I have had diagnosed twice now but have been given much to go on. Problem is it idles fine at approximately 600 rpm in neutral but when put in reverse or drive it pulls. The throttle plate opens from 4% to 14% open and the vehicle will accelerate almost to the point of shifting into 2nd gear without touching the gas pedal. A Chevy service facility recalibrated my throttle body and then replaced it with a known good on from another vehicle….same problem. I then got a new ecm and they reprogrammed it….same problem. After some time on the phone with their tech people they decided it was something transmission related…maybe torque converter related. I then took it to a reputable trans shop where they had better equipment to diagnose transmissions. They said the vehicle definitely had an issue that needed to be fixed but the trans checked out great and there were no problems there. Their tech people said the only other thing that could throw a load would be the mass airflow sensor. Not wanting to spend a lot at this point I took the vehicle home and replaced the maf with a used part from a local yard….same problem. The vehicle shows no codes and has a 4L60E trans. I am in need of some help from someone who may have encountered this problem before or has any ideas. Thanks so much for the help.

73shark

Welcome to the forum.

It almost sounds like the torque converter clutch is locking up when you put it in Drive.