6L80 Reflash?

[Knownworldwide]

Hello everyone. I do apologize if this has been covered before. I tried using the search function and I did come up with one thread asking a similar question to what I am going to ask but there wasn't a clear answer nor any instructions on how to complete the task.

Here is that thread: https://forum.hptuners.com/showthrea...t=6l80+reflash

A little backstory:

I have a 2015 Suburban LTZ. This has the 6L80 as we all know and it started doing this "chuggle" stuff at low speeds on the 2-3 shift most prominently. It will also do this "sawtooth" type engaging and disengaging on the freeway while in gear 5 or 6. Basically I believe that the torque converter is failing and I am trying to solve the issue before it leaves me stranded somewhere. My current plan is to pull the transmission, tear it all apart and rebuild it with a master kit from Circle D using their stage 2 kit. My truck is completely stock and I know this is probably overkill but I figured why not just do it better that way it should live for awhile. I also plan on using their "OE-ish" torque converter than has some minor upgrades over stock for longevity. Things like; Factory stall speed (1800-2000rpm), Billet Front Cover, Billet Lockup Apply Piston, Furnaced Brazed Impeller, Flanged Style Hub, Bearing Retainer.

My question is, on their website and from some extensive research, I need to reflash or tune or marry the ECM to the TCM? How can I do this with the MPV3? Is that possible to do or do I need to have the dealership reprogram it for me? Sorry if I am using the wrong terms as I am completely new to this stuff. I appreciate any help. Thanks for your time.

[blindsquirrel]

T43 (and T42 too) can be fully and properly flashed using HP Tuners and 'write entire' using your old tune file.

As long as it's the correct Service Number for the application.

And as long as it's a T43 that has at least had some sort of calibration in it before. Otherwise, if it's new-new (not reman) there is a small chance it could be totally blank, and if it is then HPT will not recognize it.

[Knownworldwide]

FIRST OFF let me say, thanks for the quick response! Secondly, seeing as I plan on just rebuilding my current transmission, this won't involve me changing TCM's right? As in, I am NOT buying a pre-built unit from Circle D but rather just tearing apart my current transmission and then rebuilding it. I essentially will just be reinstalling the same TCM that was already on the truck back into the vehicle right?

Forgive me for not knowing what T43 and T42 is? Is that the type of TCM that I have or is it a file version that is in my TCM?

So when you say "write entire" I would need to do what exactly? Extract the file that is on my current TCM (does that also mean get ECM stuff too?) someway using the software AND THEN write all that stuff to the TCM again?

I planned on trying to change the way and when the TCC locks up as well as delete the DOD/AFM feature.

I was just confused on what to do about the TCM tuning since it states on their website that "transmission tuning is REQUIRED"

[blindsquirrel]

Oh, you're starting from there, then.

No, you will not need to 'reflash' anything, 'reflash' meaning putting a different base calibration in the TCM. You will need to tune the transmission part of the tune for the new transmission hard parts.

T43/T42 are different types of transmission control modules, yes. T42 is for the 4 speeds and is external similar to the ECM, T43 is what's inside the 6 speeds.

You either have a whole ton of stuff to get yourself familiar with, or need to find someone to work with you. There are several guys active here on the forum that offer remote tuning (I am not one of them). Compared to the things I'm imagining that could go wrong with this and what it would cost to start over again it would not be a waste of money to just pay someone.

[Knownworldwide]

Ok then, I know you said you aren't a tuner but there are others here that are well versed in that area. I am not alien to tuning as I do own vehicles that I have tuned myself. Both are on stand alone ECUs and are boosted. I am also familiar with Holley Dominator and have tuned using that software. What I don't understand is how you would tune the transmission for the "hard parts?" I can't imagine there is a tab or selection within the software that says "which new clutches did you install?" or "Which new torque converter did you install?" Not to sound like a jerk if that is how that comes off. I could imagine there being a relearn process but is there more to it than that? Again, I am very new to HP tuners and I could be being ignorant.

[gtstorey]

Holley tuning really doesn't have much to do with GM OEM tuning, and it seems like those who start with the stand alone struggle even more than others when trying to learn OEM tuning.

[blindsquirrel]

Shift timing, shift pressures, line pressure, all kinds of stuff in the 6L80. And a lot of it will be intertwined with proper engine tuning. These are torque-based controllers, completely unlike anything used in any airflow-based aftermarket standalone.

[Knownworldwide]

Holley tuning really doesn't have much to do with GM OEM tuning, and it seems like those who start with the stand alone struggle even more than others when trying to learn OEM tuning.

I don't tune anything with the transmission on the Dominator equipped car as the car I am working on is using a TH350. A Stand alone ECU is actually my preferred method to tune with and I don't find them at all a struggle to use. HP tuners is awesome, I just don't work on many GM products. I am only here because my family mover (aforementioned Suburban) is acting up.

Shift timing, shift pressures, line pressure, all kinds of stuff in the 6L80. And a lot of it will be intertwined with proper engine tuning. These are torque-based controllers, completely unlike anything used in any airflow-based aftermarket standalone.

I was thinking that is what you meant. I have zero desire to tune the transmission to make it shift better or harder or whatever. The rebuild alone will provide all the "shift quality" needs that I am after. I only care to turn off the TCC apply for gears 1-3 (maybe 4) which appears easy enough to accomplish within the HP tuners software after a quick video watch on YT. I also want to disable DOD which also seems very easy to do.

[blindsquirrel]

Have you, um, looked through the transmission side of your tune file? Have you even pulled the file out of it yet? I'm kinda thinking you don't yet know what you don't know. These are extremely complex and the hard parts you are changing will absolutely require recalibrating almost everything about what the transmission does and how it does it.

[gametech]

Have you, um, looked through the transmission side of your tune file? Have you even pulled the file out of it yet? I'm kinda thinking you don't yet know what you don't know. These are extremely complex and the hard parts you are changing will absolutely require recalibrating almost everything about what the transmission does and how it does it.

Just yesterday I was talking about 8hp70 tuning to my neighbor who mostly does aftermarket standalone with m6 tuning, so he has not been keeping up with new automatics at all. He said "why can't the dominator control it, automatics are just turning solenoids on and off". I gave up trying to explain.

[blindsquirrel]

You could write an entire chapter of a fairly dense book just on Force Motor Current. I don't know if the 6 speeds even still use that or if it's just a 60E/80E thing, but still. That's just one tiny sliver of a fraction of what is in the tune file and how it relates to the mechanical parts inside the transmission.

[Knownworldwide]

Have you, um, looked through the transmission side of your tune file? Have you even pulled the file out of it yet? I'm kinda thinking you don't yet know what you don't know. These are extremely complex and the hard parts you are changing will absolutely require recalibrating almost everything about what the transmission does and how it does it.

I am still in the infancy stages of making a plan to fix my Suburban. I understand that transmissions are complex. I haven't looked at anything since I have not even purchased the HP tuners to yet but rather doing my research first. I don't mind learning something new. Guess here goes nothing.

[gametech]

I am still in the infancy stages of making a plan to fix my Suburban. I understand that transmissions are complex. I haven?t looked at anything since I have not even purchased the HP tuners to yet but rather doing my research first. I don?t mind learning something new. Guess here goes nothing.

If you have not actually started this process, just do a factory stock rebuild and skip all the upcoming problems. Dealing with tuning a torque based factory pcm and a 6 speed auto is the learning curve equivalent of tossing someone who can doggy paddle into the middle of the Pacific.

[2xLS1]

Every transmission shop I know that rebuilds a 6L80/90 that has had clutch material go all through it replaces the solenoid pack that includes the TCM due to contamination.

[Knownworldwide]

If you have not actually started this process, just do a factory stock rebuild and skip all the upcoming problems. Dealing with tuning a torque based factory pcm and a 6 speed auto is the learning curve equivalent of tossing someone who can doggy paddle into the middle of the Pacific.

Haha, but they can make it eventually. I have been researching the various master rebuild kits and for me, it just doesn't make sense to slap everything back together with just basic parts when even slightly upgrade parts are only literally a couple hundred more. Every rebuild kit I have found lands me around $1,300-$1,500. Maybe there are cheaper brands but as stated I have never done any of this before and I am only going with brands that I have heard before. Maybe you guys have some experience with rebuild kits that have worked for you in the past? I 100% know that I am not sticking a stock style converter back in this thing. I just ordered the Circle D 300mm HP Series converter this morning. It has a long lead time so I needed to get it on the way.

[Knownworldwide]

Every transmission shop I know that rebuilds a 6L80/90 that has had clutch material go all through it replaces the solenoid pack that includes the TCM due to contamination.

Yeah, that's what I am worried about. I couldn't tell you how much time I have spent researching and watching videos about 6L80 problems and how to correct them, Rebuild videos, modifying videos, HP tuner tuning videos, etc..

Most of them seem to leave the TCM alone and replace the pressure switch seals and disks. The only time TCM's seem to get replaced is if the owner purchases a reman transmission that already has one it it of course. I am not saying that I agree with that, only relaying what I have seen so far. I just want my transmission to live for a long time haha. I knew buying a 1500 ANYTHING GM was gonna suck! This is why I have been the owner of a 2001 Yukon XL 2500 for the last 14 years until the wife and I finally gave it away to our neighbor. That truck had 356K miles on it all original engine and original 4L80! Never any problems. I would have purchased another 2500 but they stopped making those in 2013 and the wife wanted the newer body so here I am after owning this Suburban for just over a year now and it has trans problems.

[Knownworldwide]

I also just realized that I asked this question in the wrong section. If it needs to be moved to the transmission section MODS, please do that. Sorry about that.