My 2008 Escalade ESV has been experiencing what I can best describe as torque converter shudder. The transmission never slips, never hunts for a gear and overall runs fine. However, I've noticed that at low speed cruise (55 and below), when the torque converter clutch engages, there is a terrible shudder, basically it feels like driving in a rutted out dirt road. The vibration starts mild, and can get worse. I can give it just a slight amount of gas, enough to get the TCC to disengage, and the shudder goes away.

The truck has 140K on it, and I just changed the trans fluid and filter, and it didn't help. The fluid was dirty, but not burnt, and there wasn't any large debris in it. I threw some Lubegard Dr. Tranny Instant Shudder fix in and it seemed to make it less pronounced, but still present. That could be placebo effect though.

The interesting thing is, this occured the day after the coolant hose to the heater core popped off. I never let the truck run hot or anything, and had it fixed. It did lose some coolant though, and the trans dipstick had been broken about halfway down. Could coolant have gotten into the fluid? If there was, it wasn't in the pan.

Has anyone experienced this? Could this simply be a transmission tuning issue, or is the torque converter or trans on the way out? I've always heard these transmissions are much stronger and more reliable than the 4L60e, but that tuning can be a pain.

I do have a Blackbear tune on the engine and transmission. I was going to put the stock trans tune back on, but boy the stock transmission program is awful.

Thanks everyone!

 

Gm did have an updated tcm calibration for early 6l80e with shudder. Might see if your local dealer will check for updates. It is possible to increase the pressure to the tcc in the tune to help with this issue. Some see it as a band aid fix, but I've done it and never had long term issues unless the converter clutch was already smoked.

 

I think the trans is on its last legs. No slipping, but the shudder has gotten worse. I've changed from the Black Bear tune to the stock program with no improvement. It's also had a symptom a few times of losing the gear its in, if that makes any sense. Having to slow quickly and then begin going again and it just completely lost its gear and was free reving. Pulled over and put it in park and back in drive and it ran. It didn't seem happy, but it hasn't left me stranded.

New trans on the way. Hopefully this one will last at least 8 years and 145K like the first one!