Torque converter data, trans experts inside!

[ReaperHWK]

So my truck is vibrating, checked a ton of stuff including misfire data and they all look OK. Nothing significant on that end. See thread:

Vibrations. Stumped for now.

2015 Tahoe LTZ. Has vibrations when driving and almost feels to me like a misfire. Started about a month ago and is getting progressively more severe. Vibrations are not in the steering wheel feels like engine or drivetrain to me. So whatever is breaking is breaking more lol. The vibes...

www.tahoeyukonforum.com

I logged some torque converter data and wondering if this is normal.

I logged the TC lock solenoid command, torque converter slip, and torque converter expected slip.

Driving around the slip on the converter can go from 0 to around 700 rpm, even with the torque converter solenoid command to lock it. The expected slips are way lower maybe around 20rpm.

So basically, when the computer commands the TC to lock, it still slips to over 500rpm routinely. Looks like it's not locking at all.

I read online that the slip should be less than 20rpm when it's locked, is this true?

Is there any other data I need to capture?

I think I'm going to the trans shop.

 

[ReaperHWK]

I just got off the phone with the trans shop they said it sounds like the TC. With my mileage(170k) on a 2015 they want to replace the whole tranny. $5500. They said something about at that age the pumps are shot as well and it's the best bet to get a whole new one(complete trans).

I'll have to think about it and do some more logging, still not 100% though.

 

[Geotrash]

I just got off the phone with the trans shop they said it sounds like the TC. With my mileage(170k) on a 2015 they want to replace the whole tranny. $5500. They said something about at that age the pumps are shot as well and it's the best bet to get a whole new one(complete trans).

I'll have to think about it and do some more logging, still not 100% though.

The 6L80 is a good transmission so long as the TC is dealt with. You're on borrowed time - too much more logging and you'll log the failure.

At 170K I would be inclined to install a reman/have mine rebuilt, but would specify a TC with a flanged hub and a billet cover, along with a stronger lockup clutch. That said, if you're on a tight budget and have the space/time/tools/skills, you can replace the thing in your garage. $300 for a TC plus another $200 and change for other misc parts like a rear main seal, and you're on your way.

Having a shop do it, figure $1,500 for the R&R, plus the cost of the TC. Or figure $3500-$5000 for a full rebuild. Check the 6L80 transmission thread from @NickTransmissions for what to make sure the rebuilder does for your money. Your $5500 quote is in the ballpark for a quality rebuild, as long it includes the R&R labor and comes with a warranty.

 

[ReaperHWK]

Here a log showing the slip. Please confirm if it looks bad.

 

[ReaperHWK]

Well truck is worth 11k, repair could be around 6k. Also has 170k miles and the rear quarters are starting to rust on the wheel arches.

Talked to the wife I think we are leaning toward a new one at this point. Looking online at a 2023 Tahoe RST with 20k miles, I need to look into these new ones. I know to stay away from the 6.2 though.

 

[NickTransmissions]

Well truck is worth 11k, repair could be around 6k. Also has 170k miles and the rear quarters are starting to rust on the wheel arches.

Talked to the wife I think we are leaning toward a new one at this point. Looking online at a 2023 Tahoe RST with 20k miles, I need to look into these new ones. I know to stay away from the 6.2 though.

If the truck is showing signs of aggressive rust build-up, it will cost a fortune to fix so I agree - time to move on from it...If it was healthy in all respects apart from the transmission and you liked the truck then I'd probably have it overhauled since you know the transmission will be good for a long time.

 

[ReaperHWK]

Checking a few out this weekend. This is my favorite just by features:

I thought you would like this Used 2023 Chevrolet Tahoe RST w/ Luxury Package for $60899 on Autotrader http://atcm.co/S2PVDP/2CA9E848.

I like this one because it has the max trailer package. Hard to find many with that.

 

[ReaperHWK]

Fixed the problem. Threw truck away replaced with this.

I thought you would like this New 2026 Chevrolet Tahoe RST for $87329 on Autotrader http://atcm.co/S2PVDP/2D71F840.