6L80E torque converter sudder?

[langsbr]

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!

 

[Wake]

I used Dr Trans in my 05 when it had TC shudder when locked in OD. it cured it. I believe you can add a second treatment to it if needed (check directions). It definitely wasn't the placebo effect. I read lots of reviews of that particular product and in all but shot transmissions it helped the people that used it.

I was just unhappy I didn't find out about it before I changed my front diff, which I thought was the problem. Under any low high load, low torque conditions it would shudder enough to be very annoying and it was constant whether a 15 minute run to the store or a 1hr drive to a work location on the backroads where I didn't hit highway speeds.

 

[langsbr]

It seems like the problem has subsided. I can't say for sure since I haven't driven it in a couple days, but the wife hasn't complained about it and she'd let me know asap. Got my fingers crossed that the Dr Tranny shudder fix did the trick. I still have yet to return the trans program to stock to see how it behaves. Might try this this weekend.