GM's 6L80 HP Tuning, DoD, and Torque Converters! Part 2 of 3

This is the second part of a three part series covering the 6L80/90 torque converters and their issues and failures. In this video, I go through the internals of the JMBX torque converter and show the common issues that plague this transmission. I discuss the woven carbon friction lining, the piston and damper design, the converter cover issues and also some problems that might arise when doing software tunes or using aftermarket converters.
If you need a refresher on torque converter construction, operation, and diagnosis, you can find that video here: • Basic torque converter...
Part one of this series goes through the Displacement on Demand system, along with demonstrations and problem examples on actual vehicles. You can find that video here: • GM's 6L80 HP Tuning, D...
Part three of this series goes into HP tuners and the common modifications that technicians make to the transmission software regarding torque converter clutch operation: You can find that video here: • GM's 6L80 HP Tuning, D...

[@Relisys190]

Excellent video. makes me want to get a Billet TC right away!!

[@alltheboost5363]

Great video thank you so much

[@Haithamz]

Thank you 👍🏼

[@justinlaxdal5812]

Awesome video series! Been looking for such explanation for years. I have a question for you, if you were to set the tcc slip to zero how much pressure would you increase for a 1500 truck application?

[@siuautomotive]

I would first just put slip to zero without raising pressure. The computer should increase pressure to achieve the slip you programmed it for.

[@turbodave231]

Outstanding video. Dave from Macomb Community College

[@siuautomotive]

Thanks neighbor!

[@kenmills4628]

Really appreciate all your videos. Very informative. Thank you. A lot of people have swapped out the stock 6l80e tc with the 6l90e tc found in the zl1/cstv (GM part #24242552). Seems as though it’s a bit more “heavy duty”. Any thoughts on that? Also, the latest beta of VCM Suite has added mapping for desired tcc pressure on a lot of the operating systems. Seems to help many with aftermarket converters in eliminating slip by upping those pressures. Just thought I’d pass that along.

[@siuautomotive]

That's really good to know. I'm downloading the Beta version now. It's amazing how much the TCC operation varies between different models and generations. The TCC apply speed for example. On the later TCMs they don't change the speed much between 0% and 100% throttle, whereas on the earlier TCMs they change the TCC apply speeds like you'd expect. I always felt there was more to these later units than what we can see on HP Tuners, even though they provide a ton of info. Maybe the Beta will include some of those differences. I'll look into the CTSV converter differences. It might be the captive clutch design, which has more holding force, but it's still plagued with a whole slew of other issues. I actually have a CTSv at the school that was donated. The tune on that car is much different than the trucks. Thanks for watching the video. I'm still learning as I go, so there's bound to be things I forget to mention or I simply don't know, lol!

[@maxthemadtuner]

What’s the stock stall speed on the 6L80 and 90e?

[@Dusty_Bottoms_]

What about the 8L90?

[@sunzoutgunzout8887]

So this i dont understand 6l90 2800 twin disc billet tqvtr setting tcc slip to zero causes tqvtr to engage fully causes stalling?

[@20tea]

Hmm, was thinking about swapping to the 6l90 tc myself. I have heard they're more heavyduty. I have the non DOD 6.2 and thinking of a transmission rebuild with a billet TC. Any need for a reflash of the transmission computer or a tune?

[@kenmills4628]

From what I’ve read, it’s a direct swap. No tuning needed. However, it does have 6 mounting bolts, but 3 still line up with the 6l80 flex plate and people roll with just the three.

[@kenmills4628]

I may have misunderstood your question. If you’re asking about swapping the entire transmission, I’m not sure of what may be different with the tcm or if you can just use your original tcm. My understanding is it’s just some of the hard parts that are different between the 80 and 90 and you could just swap out those in your 80 to beef it up. Maybe someone else will come along and confirm.

[@20tea]

@@kenmills4628 Sorry, I was typing fast and corrected it. I'm looking for a way to add a more durable TC. Looks like there's a billet TC that's compatible between the 6l90 and 80, so I may try that out. Not looking for any high stall or anything, just a strong TC for towing and reliability.

[@siuautomotive]

Yes Chad, I'd do the tune that I do in part three and reduce the slip speed to zero (if it isn't already) and increase the pressures 10% (but only if you have a billet converter. If the converter builder uses an OE woven lining, then I wouldn't worry about the slip, but I would still eliminate TCC application in 1,2,3 gears. That 6-lug captive clutch converter has more friction surface area (two friction surfaces vs. one), but it's also prone to deflection and other issues. I think an aftermarket with a billet cover is the best option.

[@20tea]

@@siuautomotive Thank you! Exactly what I was interested in hearing.

[@oneman723]

Should you still turn the converter off 1-4 if you pull trailers?

[@siuautomotive]

I would, but if you’re in 4th a lot while towing, you could just defeat tcc in 1st through 3rd.

[@SMOKEY-JAYS-DIESEL]

Hi 👋 where can I get the stock file for the 6l90E transmission?? 2014 Chevy Express 3500 LGH Duramax HP tuners

[@siuautomotive]

If you create a free account in hptuners, you should be able to find a stock tune in there repository.

[@SMOKEY-JAYS-DIESEL]

@@siuautomotive I have a account with HP tuners and when I'm send on their where do I go to find the stock files that people have uploaded? AKA repository.?

[@siuautomotive]

You log into hptuners and when you go to “my account” you’ll see a link for the repository. Unfortunately I looked and there isn’t a file for your vehicle. You might try signed up on the forum and asking there, or joining some Facebook groups and asking there. Lastly, if you can find a used truck on a lot somewhere, maybe you can pull the tune that way.

[@SMOKEY-JAYS-DIESEL]

@@siuautomotive awesome thanks very much for your help and support 🤝🙏🏻🙌