Torque converter starting to quit?

[thefrey]

I'll start with I don't know squat about torque converters and transmissions, but here's the scenario.

I parked it for probably 10 days while on vacation and then came back, started it up, drove 300 miles on a road trip for work, no issues. Next day, about 50F going up a slight incline at about 70-75 I felt a slight hesitation... then maybe one or two other times in the next 5 seconds. Day went on drive about 100 miles and felt it one or two more times. Have driven about 600 miles since then and haven't felt anything since. I have not felt this the whole time I have owned this vehicle. It has 228.5k on it right now.

Something weird that might be TC related too is usually the first 10 seconds of my drive it almost feels like what I would describe as a flat spot in a tire, but I know 100% it's not tire related.

My tuner changed my torque converter lockup I believe in gears 1-4 so it saves my torque converter and that was about 15k miles ago.

I do not know the history on the fluid, I haven't changed it since I've owned it but I am scared to touch it given the controversy about fluid swaps...


Is this something that I can wait until it gets worse or do I need to address it asap? I don't have a scanner to read pressures or look at anything.

 

[dkad260]

Did you check the fluid level after this happened? Engine idling, level surface...the fact it acted up on an incline makes me think and hope it's fluid level related.

The next time it happens drop it down to 5th gear and see if it replicates. That gear is easier on the converter clutch than 6th, might tell a story.

 

[B-train]

What's the color of the fluid? I'd advise a pan drop and filter change. That'll refresh approximately 40% of the fluid with trans cooler factored in (others can correct me if my math is off). Safest option since you don't know the history IMO.

 

[Marky Dissod]

I do not know the history on the fluid, I haven't changed it since I've owned it but I am scared to touch it given the controversy about fluid swaps.

That 'controversy' applied - past tense - to Dexron3 & older clutch materials.

I'd advise a pan drop and filter change.

As would I, with Dexron6 or fully synthetic Mobil 1 Synthetic LV ATF.

 

[Sgt1411]

I have a 2007 Cadillac Escalade at my vacation property, the vehicle has 180,000MI but only one previous owner and I know him and how it was driven in west coast of US. Vehicle was driven well and has only had 91 Octane since new. No oil leaks on engine or transmission. I have a transmission issue where every once and a while during regular level 30-50MPH driving the transmission will give a hard "Clunk" sound and feel.

Transmission fluid still dark red, checked hot on garage level floor and is full.

Talked to local GM dealership they are very hesitant to do fluid swap including torque converter as they can suck it out nowadays for $299. Im just wondering what the big controversy is over changing the transmission fluid in these older trucks.

Can some please educate me?

 

[West 1]

I think doing a flush on a tranny with 180k on it is a bad idea. All the material sitting in the bottom of your oil pan can be stirred up and cause tranny issues. A flush usually means they remove one tranny line letting fluid pour into a catch while they pump new fluid into where that line should have been connected. It does repalce all the fluid in the system which is good, it stirs up the dirt already in there which is bad.

I would not hesitate at any mileage to drop the tranny pan which drains 1/2 the system fluid, replace the filter, clean the oil pan and reinstall with new fluid. After driving for a while maybe do this one more time to get most of the old fluid out of the tranny. I trust this much more than the flush program.

Going back to 2004 I first heard of the flushes and thought what a great idea, took my 2001 Denali in with 57,000 miles on it and had a flush done. Tranny failed at 59,000 miles. I also had a 95 Suburban at the same time, it had 150,000 miles on it at that time and I had the flush done on it also. Tranny failed at 155,000 miles. The tranny rebuilder i use is a friend, he said the flushes stirred up the junk in the tranny pan and plugged the shift valving in the trannys causing failure. One was a 4L65E HD in the Denali the other trans was a std 4L60. I have never used a flush since. Just standard pan removal and filter replacement.

Maybe a combo of remove pan, install new filter and then get a flush would be safe?

EDIT: I don't believe it was a reverse flush. They just removed one tranny line at the radiator and tapped in to their flush system.

 

[mikez71]

I'm never getting a flush after hearing your experiences! Were your flushes 'reverse' flushes?
Because that would seem more risky to me than a standard flush.

But I agree, never anything wrong with a filter and fluid replacement..
I'm still scared to do my filter bacause I'm scared of stripping/breaking the exhaust bolts that seems semi-common..

Could the clunk be the slip yoke binding or maybe trans/engine mount if it happens during a shift?

 

[donjetman]

@Sqt1411
Yes, you need to have BOTH the fluid AND FILTER changed. This should be done every 50k miles with the 6L80 tranny.
Your torque converter if original is at the end of its life.

 

[Sgt1411]

@Sqt1411
Yes, you need to have BOTH the fluid AND FILTER changed. This should be done every 50k miles with the 6L80 tranny.
Your torque converter if original is at the end of its life.

Got the transmission fluid sucked out and the mechanic said it was toast, blackish red not the normal red and strong burnt smell. New full synthetic replacement and I have to say there is a noticeable difference.

 

[rdezs]

It's never too late....

... And you won't even find dust in the bottom of the transmission pan.