2019 Tahoe Torque Converter Replacement

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TahoeEd

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Just going to add a recommendation I just made in another post especially on the bypass valve, cooler and pan to keep your trans cool. My torque converter blew on Christmas Eve on my 2018 at 65k miles, shed a ton of glitter into the fluid and ended up turning into a reman transmission after having AAA tow it nearly 300 miles home. Luckily I felt the hesitation/slip/flare shifting and saw the temp rise and pulled it off the road. I have the Range AFM disabler adapter too and was checking to see if that had anything to do with it but discovered that was not likely.


The issue though unfortunately here is since you are already at the dealer (which can't blame as you are still in warranty) you are stuck with their runaround and also OEM parts with all of their flaws. Most good aftermarket transmissions come with a billet converter cover which addresses the design flaws of OEM with it distorting around where the three fittings are welded to the plate. I would insist if nothing else while at the dealer and if they are already into it they do replace the converter anyway with all of the fluid AND install the updated thermal bypass valve that opens at 158F to keep the temps down per their own TSBs recommending that happen with any transmission work and then once you get the truck back consider at least a transmission cooler now, aluminum pan when you do fluid again next time (this is probably excessive but I do my fluid every year but I also get away with that process easier as I don't need to do the filter as often given the pan drain plug). You might not need the Surecool kit if you get the updated thermal bypass but mine runs in the high 120s F on the highway, 130-135 in town.

With Auto 4WD I would suggest keep it out of there. Consider just shifting to 4 High if you are getting into snow or ice conditions but obviously not on dry pavement. Given your mileage and the nature of what they already need to do I would suggest have them do the transfer case fluid (If not already when dropping the trans). Your differentials too while they have it IF the price to do so is not more than comparable independent shops.

This is just from personal experience - I actually stopped using dealers years ago especially with the runaround, money grab tactics and poor/overpriced repairs on all three of my GM trucks, one of which could have turned into a fire with one of those repairs being oil cooler lines not installed properly. Before your warranty expires I would advise find a really good independent shop near you and develop a good relationship. That will go a long way to keeping your truck on the road and the costs and frustration of doing so much more tolerable.

Good luck and hope everything works out for you either way you proceed.
I don't know how I missed your replay earlier, sometimes it's hard to read everything on my phone. Thank you very much for the suggestions. I actually have the updated bypass valve which I bought about this time last year, but did not install it because I didn't want to do anything the dealer could argue I voided the warranty. I think it is a great idea to look for an independent shop for future out of warranty work and will look around my area for one.

As far as the auto 4WD, this is my wife's daily driver and she drives about a mile to work and back. The day before we brought it in, the roads were very slushy so she turned it on. She forgot to turn it off before dropping it off at the dealer, but in no way is the vehicle run with it on very often. I just hate that it gave them another excuse for what could be the problem even though I rarely drive with it in auto 4WD and I'm the one that noticed the shutter.

Thank you for all the responses, I appreciate it.
 

NickTransmissions

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No, I don’t believe I need any specific information about the vehicle. I was more looking for opinions on what I should take from the conversation with the dealership. Yesterday they claim no problem at all and refuse to drop the pan. After persisting they agree to drop the pan but say everything is as it should be. Then they are replacing the torque converter. Seems like I might not be getting the whole story and want to know if I should be concerned with more potential problems. Do the pictures indicate anything other than normal wear for a vehicle with 45,000 miles?
That fluid looks like it has 345k on it...Shuddering is converter a lot more often than not. Replacing it is a giod call however the problem is that the dealer is going to put the same POS JMBX converter w/that stupid .022" converter clutch which gets worked to death, failing early and often.

If it were my vehicle, id yank the unit and go through it though i understand not everyone has the time or tools for that. At very least, flush all that stuff out, put all new fluid. Tell the dealer (assuming no work has been done already) to do the flush then take it to an independent transmission shop that knows these units. Let them look at it, those pictures and they will give you their opinion on what next steps should be. If the TC is replaced, make sure they install a converter with a .070" thick Borg Warner high energy converter clutch. Then have them flip the pill on your TBV, per computernerd's post.

If all this has been said already (i didnt read responses posted after your reply to me), consider this positive reinforcement.

Quote my post or mention me if you reply; I had no idea you had initially and just happen to see it just now while scanning the forum.
 
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TahoeEd

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Thanks @NickTransmissions, I greatly appreciate it. What should I look for in an independent shop? We have a local shop that services our company trucks, but he’s not a transmission specialist.
 
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NickTransmissions

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Thanks @NickTransmissions, I greatly appreciate it. What should I look for in an independent shop? We have a local shop that services our company trucks, but he’s not a transmission specialist.
You're welcome. Ask around, including your local shop; also check Yelp and other local service / product review sites or even Facebook/Linked-In. The shop that works on your transmission (or vehicle, for that matter) should possess three attributes:

1. Sufficient body of knowledge of the transmission you'd be bringing to them for overhaul, including how to systematically inspect, test and diagnose to identify the specific reasons for your transmission's failure
2. A validated, proven rebuild strategy for the unit (i.e. they know exactly what parts to replace, procedures to perform, pattern failures to address and corresponding updates to make to prevent recurrence of the same or other problems
3. Willingness to work with you, meaning they patiently answer your questions as well as ask questions of their own about how you currently and/or plan to use the vehicle, vehicle/trans service or repair history and goals/preferences (i.e. what's 'success' mean for you when it is all said and done).

See my 6L80 Info thread (if you haven't already) for more details around parts, procedures, common problems and fixes, etc - link is in my signature.
 

BMPNUGLS

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I recently dropped the pan on my 2016 Denali XL with the 8L90 at 145K miles….it previously had the fluid flush/replace with the updated fluid via the dealer under my extended warranty at ~70K…so pan/filter had not previously been replaced….my magnets at 145K did not have nearly that much stuff on them! Which was a bit of a relief for me since I’ve been concerned about the transmission life.

I installed the thermal bypass at the same time I dropped the pan (as well as replaced the solenoid/temp harness because it would give me a code once in a while)….now ~15K later transmission feels better than it ever has and never gets above ~125*. I also have had the Range AFM disabler installed since almost day one when I bought it new.

Just my $0.02…frequent (more frequent than I initially did) fluid and filter changes and the thermal bypass should let these transmissions last quite a few miles!
 

BlackBrud

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Just adding a note of support here. Bought my 2019 with 88K miles on it. I don't think the ATF was ever changed, so I dropped the pan, replaced the filter, and cleaned the magnet. The fluid was really dark and smelled burnt. I also added a full ATF thermostat bypass so it always goes to the cooler. I replaced about 5 qts of ATF during my first pan drop, and then I've since done one more drain and fill of the ATF with Amsoil ATF. In a month or so, I plan on doing my last drain and fill for a bit - I should have most of the fluid replaced by then. I'm hoping to keep it alive past 100K, and then hopefully one day I can take a trip to Vegas to get a nice build from @NickTransmissions .

I also replaced the fluid in both diffs and my transfer case with Amsoil fluids - might not be a bad idea in your case.

I hope your issue gets sorted quickly!
 

arkie

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I recently dropped the pan on my 2016 Denali XL with the 8L90 at 145K miles….it previously had the fluid flush/replace with the updated fluid via the dealer under my extended warranty at ~70K…so pan/filter had not previously been replaced….my magnets at 145K did not have nearly that much stuff on them! Which was a bit of a relief for me since I’ve been concerned about the transmission life.

I installed the thermal bypass at the same time I dropped the pan (as well as replaced the solenoid/temp harness because it would give me a code once in a while)….now ~15K later transmission feels better than it ever has and never gets above ~125*. I also have had the Range AFM disabler installed since almost day one when I bought it new.

Just my $0.02…frequent (more frequent than I initially did) fluid and filter changes and the thermal bypass should let these transmissions last quite a few miles!
I also have a 16 Denali, and would love to know the details on your trans mods. Can you DM me the part numbers you used?
 
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TahoeEd

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Thank you for all the input.

They ended up installing a remanufactured torque converter and did a complete flush and filter change. I had my wife ask if they replaced the thermal bypass when she picked it up. The answer was less than encouraging. The person she spoke with (I assume he is a go between for the customer and the technician and not a mechanic) said they reprogramed it and it will learn your driving after a few miles. This is also the person that said there was no metal and everything looked fine.

I spoke with my local mechanic and he gave me a couple of names he would trust with a transmission, so I will reach out to them and just have a conversation on what they think should be done next. I will at least install the updated thermal bypass I bought last year and continue using the range device. I don't really have to worry about voiding a warranty as the powertrain is up in a couple of months and the remanufactured torque converter only has a 12 month 12,000 mile warranty.
 

Fifty

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@NickTransmissions

I’ve been trying to find a trans shop that is familiar with the 8l90 for about 2 years.

I’m in the east bay area of California

No one.

SoCal yes, but that’s a 14 hour drive each way.

Can anyone recommend a shop in the Bay Area? My 2015i has a 2nd gear flare when it’s cold and the shutter.
44k on the clock.

It needs to be gone through. I figured a converter and a rebuilt trans. I don’t want any more issues and I want to be able to run 35’s off-road eventually.
 

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