6L80/6L90 harsh violent downshifts.

[KLUG'S SS]

So anytime I have ever disabled torque management on down shifts on the 6 speeds I will get a very hard violent nasty feel on power down shifts. Like rolling at any speed whether it be wanting to pass someone at 50-60 mph or just rolling at 20 mph it feels like it damn near wants to break something in the driveline! I always leave the upshift torque management enabled and just “tune it” but would rather just disable TM on the downshift side of things.

Who else has seen/felt this and if so have you come up with a solution? Haven’t played with it in awhile now because as I said it hits so damn hard I am afraid of what might come of it. ie broken parts. Lol.

[KLUG'S SS]

No particular tune file to post because I just generally have seen it on any 6 speed I have tried to disable the downshift TM on. I’m assuming either it’s something simple I am missing or it’s one of those things of just is how it is with these.

[5FDP]

My advise is to never touch it, ever.

The less you fuck with the better, the 6L80e is not something TM should be altered much at all. The TM is what keeps it alive and functioning like normal.

[KLUG'S SS]

Yea been tuning them for several years, MANY of the 6 speeds right from the time they were first introduced and as I said I lessen the TM some on upshifts and I’ve never even played with the rest of the torque management unless it was on my own personal vehicle just testing and playing around with things. Just nothing more than being curious! As many as I’ve tuned over the past almost decade nobody has ever reported hurting a trans yet with my tunes so obviously doing something right. Lol

I know for a fact that many have all but disabled all of the torque management in the 6L80/6L90 units and if they were seeing that harshness and if so how they were dealing with it is all I was curious about.

[KLUG'S SS]

Basically in a nutshell I can attest as much as anyone that?s been tuning these creatures for awhile now that it seems to me at least that less is more with them as far as making a slew of changes in the tune.

Hell I very well could be approaching it differently and others are making wholesale changes to the trans tune with really good results, I don’t go perusing through other tuners tune files seeing what they did. Which is what brings me to original question that started the thread with. .

[Area47]

i personally leave it active and back it down at wot for specific applications. you can adjust torque load and rpm range on how much you want to leave in or take out. it's not just one set number. your downshift issue is most likely caused by too much pressure, or too fast on downshift speeds.

[KLUG'S SS]

i personally leave it active and back it down at wot for specific applications. you can adjust torque load and rpm range on how much you want to leave in or take out. it's not just one set number. your downshift issue is most likely caused by too much pressure, or too fast on downshift speeds.

Right. For "most" applications as far as upshift torque management goes I have a certain routine I follow that gets them shifting pretty well while still allowing for some torque reduction through the shifts. I generally don't go making many changes hardly at all honestly as far as shift pressure and shift times go and the trans feels quite improved with nice quick shifts. So yea maybe on the downshift side of things with the TM just disabled and even the stock pressure and shift times that I do indeed have set how it is from the factory is too much. Thanks for your input.

[Frost]

I avoid this too, but in the past when messing with it, the "bad" downshifts are the pass through neutral downshifts. In toying, I have disabled all pass-through neutral, and in Sport, disallow 6th gear. That 6th to 2nd drop is a doozy without TM as it goes through N. It's unmanageable in higher HP cars without TM, period. The annoying thing in disallowing pass-thru-N down shifts is that in regular drive mode, it goes 6-5-2(or3) and the step is delayed. In sport, that 45 MPH shift would be 5-2 in one jump as described above. Just something to try if you are playing around.

[ddtech]

Dont let it downshift in power, Setup TUTD to auto upshift at wot.
I have cars shifting around .1ms constantly and retain almost 100% TM on 6l80s and 90s. Turning off TM completely is asking to shear a intermediate shaft or input shaft. There's been plenty of discussion on this..

Search Tre-Cool and there's a few tips and tricks here and there.

[KLUG'S SS]

I avoid this too, but in the past when messing with it, the "bad" downshifts are the pass through neutral downshifts. In toying, I have disabled all pass-through neutral, and in Sport, disallow 6th gear. That 6th to 2nd drop is a doozy without TM as it goes through N. It's unmanageable in higher HP cars without TM, period. The annoying thing in disallowing pass-thru-N down shifts is that in regular drive mode, it goes 6-5-2(or3) and the step is delayed. In sport, that 45 MPH shift would be 5-2 in one jump as described above. Just something to try if you are playing around.

Thanks for that advice Steve. Like I said it's just more one of those things where I am trying to go further in depth with these clutch to clutch transmissions and wanting to understand every little thing about them and I'm just being anal. LOL. I've tuned many of them and I and the customer has been pleased overall with the difference in the transmission with just calibration work. I NEVER disable upshift torque management on these transmissions, I think they seem to shift the best with some degree of torque management left in there. Just my personal opinion of course on that.

[KLUG'S SS]

Dont let it downshift in power, Setup TUTD to auto upshift at wot.
I have cars shifting around .1ms constantly and retain almost 100% TM on 6l80s and 90s. Turning off TM completely is asking to shear a intermediate shaft or input shaft. There's been plenty of discussion on this..

Search Tre-Cool and there's a few tips and tricks here and there.

Same here, I have the 6 speeds shifting nice and quick while retaining like you said even ALL of the upshift TM. After plenty of reading over the years of guy's personal tuning experiences with these units and how they go about changes to the calibrations along with hours and hours of my own testing I've just kind of come up with my own ways compared to others of getting these animals shifting much better. Definitely wouldn't say that their is a completely "right" way or completely "wrong" way to go about tuning them, same goal of nice quick consistent shifts can be achieved through several different techniques.