GM 6L80 Transmission Information Thread

[NickTransmissions]

One thing I've noticed is the wide variety of prices on converters, even one claiming "billet covers"
- The big names like Yank, Circle-D, etc. seem to want about $1300 for a billet converter from their websites and they are all higher stall than stock
- There are some more obvious names playing in the high $100's like Monster and ProTorque that seem to hold to stock stall if you want
- Then there's this section down around $500 like the reman on RockAuto or a RECON from Transendence

Not all of these list specs to look for the lockup clutch thicknesses as Nick suggested. How does one go about shopping for something that's a definite step up from the stock JMBX in terms of durability without going all in on increased power handling like a 2600rpm stall Circle-D?

I'd recommend looking in your area for a reputable torque converter rebuilder...I'm fortunate to have one here in Vegas and he does all my torque converters, regardless of application, stall, configuration, etc...Many of the big converter builders will order the same parts from Sonnax to build the converter; some will have proprietary parts.

The RECON converters are basically stock replications; RECON is a very large converter reman company who builds torque converters for all makes/models sold in the US; they will use the same spec of converter clutch that the factory uses. There's a few others as well...Yank and Circle D specialize in racing / street-strip converters so they don't offer too much in the way of factory stall options. Florida Torque Converters is a good company and builds a variety of converter types for any given year/make/model.

Converter clutch thickness should be .050-.070, BW high energy is preferred.

 

[CTX-SLPR]

Nick,

Perhaps an odd idea but since there’s a good number of us who want to rebuild our 6L80’s but there is an investment in tooling, have you ever thought of having one or two of the mandatory tools for rental like auto parts stores. I.e. having the slide hammer for the case pins for rent for cost of the tool deposit and then something like a $20 fee + shipping for the trouble of having to deal with shipping it out on occasion?

 

[NickTransmissions]

Nick,

Perhaps an odd idea but since there’s a good number of us who want to rebuild our 6L80’s but there is an investment in tooling, have you ever thought of having one or two of the mandatory tools for rental like auto parts stores. I.e. having the slide hammer for the case pins for rent for cost of the tool deposit and then something like a $20 fee + shipping for the trouble of having to deal with shipping it out on occasion?

Id never do that for the simple fact thet if someone decided to keep it, Id be out. Way too much hassle for no substantive benefit.

Besides, you're looking at the tooling costs as though they were operating expenses when they are actually capital expenses.

Capital expenditures are incurred to acquire assets that can generate cash flow or reduce operating costs. They can be depreciated to reduce taxable income in most cases or resold to get back some of the initial investment in the even the case for them no longer exists (ie you sell your vehicle and buy one with a different transmission). They are not operating costs that, once incurred in exchange for a service, are deducted straight off the top line with zero potential for cost savings, cash flow generation or skill development on your part.

If you think you can do the work yourself, but for the lack of the special tools, buy the special tools. Its less money in capital costs than you're going to pay someone to do the work for you (operating cost).

Besides, you wont have to guess/hope you're getting what you paid for and will have a skill that will last you a lifetime with the tools to go with it.

 

[CTX-SLPR]

Nick,

I get your point about not wanting to hassle with this. I can’t find a listing for the size of the roll pins in the case for the parking pawl, Would you be able to measure one? I’d rather get a slide hammer kit with the collet style ends as I do have more uses for that sort of thing for $350 than just the single size of the DT-48550.

 

[NickTransmissions]

Nick,

I get your point about not wanting to hassle with this. I can’t find a listing for the size of the roll pins in the case for the parking pawl, Would you be able to measure one? I’d rather get a slide hammer kit with the collet style ends as I do have more uses for that sort of thing for $350 than just the single size of the DT-48550.

If the parking pawl housing isnt leaking, no need to change it. You should be able to get the selector shaft retrntion roll pin out with diag cutters...Apart from that, any collet style puller-slide hammer set should work (prob better than the tool itself which isnt nearly as heavy as it needs to be for pulling out that roll pin).

 

[jerryksr]

Hi Nick! What an outstanding and informative thread! Only problem is, it's way over my head.....LOL.
Anyway, I have a 2016 Tahoe 4wd Z71. 73K. No problems so far, pulled the dipstick, fluid very clean. I'm hearing the horror stories on this trans. Someone said problems start at 70K, called a local mechanic, he said if you made it past 35K you should be good. Hmmm. Never serviced the trans. Was going to take to get flushed. Coworker took a Honda to get flushed, (110K) and dealership told him not to, things are 'fused' and flush would cause problems. Should I do anything at all?
Thanks, Jerry

 

[NickTransmissions]

Hi Nick! What an outstanding and informative thread! Only problem is, it's way over my head.....LOL.
Anyway, I have a 2016 Tahoe 4wd Z71. 73K. No problems so far, pulled the dipstick, fluid very clean. I'm hearing the horror stories on this trans. Someone said problems start at 70K, called a local mechanic, he said if you made it past 35K you should be good. Hmmm. Never serviced the trans. Was going to take to get flushed. Coworker took a Honda to get flushed, (110K) and dealership told him not to, things are 'fused' and flush would cause problems. Should I do anything at all?
Thanks, Jerry

Thanks, Jerry! Appreciate the feedback...

I'd have it serviced, whether you do a full flush, pan drop w/filter and fluid change or both is up to you but never changing the fluid is what primarily leads to premature failures in these transmissions (followed by the poorly designed JMBX torque converter).

Not sure I'd agree with your local mechanic about being 'good' after only 35k since that would apply to like 99.9999% (i.e. six-sigma level quality) at that point in the transmission's life cycle. We start seeing failures around your mileage (70k) and up, mostly due to torque converter where the trans is a collateral casualty followed by cracked 1-2-3-4 piston and leaking 3-5-R drums, especially in the pre-2012 units.

I also don't subscribe to the widely held belief that flushes cause transmission failures...I hear all kinds of things, including flushes will blow out the seals to flushing dredges up all the contaminants...The problem with those assertions is that seals, sealing rings, etc regularly see 125-150+ PSI at 200+ degrees during the course of normal operation while fluid is continuously circulating everything imbedded within it throughout the transmission constantly...So flushing being the reason a transmission failed (and not due to parts/components already on their last legs, worn, etc) doesn't make any sense to me.

Like any other mechanical device, if the transmission isn't properly maintained then it's not going to last as long as if it were, all other things equal...So you have a better chance at maximizing it's longevity and mean time between overhauls if you keep up with maintenance schedules...Dex6 can go about 55-75k then should be changed (desert/hot arid environments should do changes at 50-60k).

 

[jerryksr]

Nick,
Thank you so much for the quick reply! Knock wood, hopefully I'm one of the 'lucky' ones. lol
Thanks again!

 

[NickTransmissions]

Bumping this thread with a new video: Unboxing, Inspecting and Testing a Monster Transmissions' 6L80 Valve Body

Enjoy!

 

[DamThatRiver24]

Dex6 can go about 55-75k then should be changed (desert/hot arid environments should do changes at 50-60k).

6l80 here (2010 Tahoe LTZ). Have heard from a lot of folks (including a few on here) that 30-35k is the severe schedule that we should be sticking to on these transmissions.

For me, that's about once a year, lol. Is it your opinion that it could probably go another 20k each cycle and be fine?

 

[NickTransmissions]

6l80 here (2010 Tahoe LTZ). Have heard from a lot of folks (including a few on here) that 30-35k is the severe schedule that we should be sticking to on these transmissions.

For me, that's about once a year, lol. Is it your opinion that it could probably go another 20k each cycle and be fine?

The figures in the post you quoted was for daily drivers, crusiers and mild performance applications. HD/Serious work, severe off-road, HP/SS, full race and other non stock applications will require more frequent fluid changes, common sense right?

If your usage pattern fits the above, every 30-50k somewhere in there is recommended. More severe the duty, more frequent the fluid service.

 

[Sgt1411]

My 2007 Escalade has the 6L80E transmission. (6-SPEED AUTOMATIC, HEAVY-DUTY, 6L80E, ELECTRONICALLY CONTROLLED) The transmission was apparently rebuilt a few years back and has absolutely no fluid leaks anywhere. Checking fluid shows it is red and full no signs of discoloration. The vehicle has around 168,000 miles on it but only one owner before me and I knew him so I know the history. The vehicles runs very well but I had a question about drivability characteristics and perhaps its just me not understanding those dynamics with this older transmission.

If your driving along at 30-40MPH and your slowing for a red light so you let off the throttle. The light goes green before you come to a full stop so now you apply throttle and there is a second or two delay and then a bit of a clunk like the transmission was in the wrong gear and had to drop down a gear. Is that a normal behavior or indication of something?

 

[NickTransmissions]

My 2007 Escalade has the 6L80E transmission. (6-SPEED AUTOMATIC, HEAVY-DUTY, 6L80E, ELECTRONICALLY CONTROLLED) The transmission was apparently rebuilt a few years back and has absolutely no fluid leaks anywhere. Checking fluid shows it is red and full no signs of discoloration. The vehicle has around 168,000 miles on it but only one owner before me and I knew him so I know the history. The vehicles runs very well but I had a question about drivability characteristics and perhaps its just me not understanding those dynamics with this older transmission.

If your driving along at 30-40MPH and your slowing for a red light so you let off the throttle. The light goes green before you come to a full stop so now you apply throttle and there is a second or two delay and then a bit of a clunk like the transmission was in the wrong gear and had to drop down a gear. Is that a normal behavior or indication of something?

Is this issue new or has it always behaved this way? If the latter, for how long?

 

[donjetman]

@Sgt1411

search "clunk" and/or "Klunk" on this forum.

motor mount(s), front diff mount(s), transfer case worn chain.

 

[CTX-SLPR]

Nick,

Is there a place you can buy a preassembled pump and bellhousing? Local guys seem to have gotten out of the game of doing job work so looking for a contingency plan if the pump is damaged when I pull the trans apart for testing and a Zip Kit. I can find new ones in knock down kit form but without the test tool to see if the vanes are too tall a preassembled one seems like a better bet.

Thanks

 

[tkdgirl]

So this is probably going to sound like a dumb question but let me give a little bit of back history.

My transmission blew in July replaced with a new one direct from GM. GM had to reprogram the TCM which meant the custom tune I had was out of sync. Therefore a ton of bad clunking and downshifting. When I had the original custom tune flashed again it got better but the clunking is still there primarily at slower speeds or when I have to make a sudden stop from over 50 mph.

The past week the weather's been great so I haven't been using my AC. No clunking.

What could be going on with the AC that would affect the transmission?

When the transmission blew I was towing in tow mode and had the AC on.

@NickTransmissions I honestly don't know what to do at this point.

 

[Sgt1411]

Is this issue new or has it always behaved this way? If the latter, for how long?

Since I have owned it, this is the driving behavior.

Approximately 12-15 months, isn't getting worse just the same.

I'm just interested to know from a subject matter expert if this is a normal characteristic of these trucks or something needs replacing

 

[Sgt1411]

@Sgt1411

search "clunk" and/or "Klunk" on this forum.

motor mount(s), front diff mount(s), transfer case worn chain.

Thank you

 

[NickTransmissions]

Since I have owned it, this is the driving behavior.

Approximately 12-15 months, isn't getting worse just the same.

I'm just interested to know from a subject matter expert if this is a normal characteristic of these trucks or something needs replacing

This can be normal as the transmission/TEHCM/PCM has a split second uncertainty as to exactly what the vehicle is doing between the time you let off and the time you reengage the throttle so it's making split second decisions on what gear you need to be in based on all that data streaming into the THECM/PCM. If it's happening all the time and the shifts become overly harsh then that would indicate problems, either in the torque converter, transmission or both.

I'd suggest taking for a test drive with your bidirectional scan tool plugged in and live transmission and torque converter data displayed so you can spot any anomalies in the PIDs. If so, begin your diag from there.

 

[NickTransmissions]

So this is probably going to sound like a dumb question but let me give a little bit of back history.

My transmission blew in July replaced with a new one direct from GM. GM had to reprogram the TCM which meant the custom tune I had was out of sync. Therefore a ton of bad clunking and downshifting. When I had the original custom tune flashed again it got better but the clunking is still there primarily at slower speeds or when I have to make a sudden stop from over 50 mph.

The past week the weather's been great so I haven't been using my AC. No clunking.

What could be going on with the AC that would affect the transmission?

When the transmission blew I was towing in tow mode and had the AC on.

@NickTransmissions I honestly don't know what to do at this point.

The AC system (specifically the compressor) places some marginal load on the engine as it's working so it's possible that's throwing off the tune, though not likely since tunes would account for that. Bear in mind, this is a guess on my part as I'm not a tuner and have no experience working with vehicle programming software. I'd consult your tuner or whichever company made your tune to see what they have to say. Sorry I can't be of more help with this one.