2016 GMC Sierra 5.3 A6 2-3 upshift too firm, NEED HELP

[santeegreen]

I accidentally posted in the V8 Engine Tuning section.

A little bit of background, I had a decent amount of experience tuning the Gen III 4L60's, and when I purchased my new 2016 sierra with the A6 I was blown away at the amount of tables in the transmission section. I did purchase a "tuning book" from a very very well known company and applied the theory and settings they had to offer into my tune. The truck runs absolutely PERFECT with the exception of the 2-3 upshift, it hits so dang hard it's just not pleasant to drive. Under very light load it shifts smooth, and under 3/4-WOT it shifts great, its right in the middle is where i'm having the issue. I have tried extending the shift time longer, didn't help, I've tried lowering line pressure, didn't help. I've tried everything I thought would work, with no solution. I've tried everything I can think of and I am now here to see what help I can receive. If needed i'll get some scans and post, I can also post my current tune file if needed. Wasn't sure if someone knew right away what setting might help that i'm not seeing. Thank you.

**** Currently the truck is lifted with 35" tires with stock 3.42 gears, so shift points are adjusted quite a lot, intake, exhaust and that's it. ****

https://forum.hptuners.com/showthrea...shift-too-firm

[santeegreen]

This was my tune file with Transmission master Enable/Disable "Disabled" for upshift. Shifts fantastic with the exception of the 2-3 upshift, feels like i'm being rearended under partial throttle between about 2000-4000 rpm, below those rpm's/load it shifts fine.

Andrew's 2016 Sierra NEW TUNED TM Disabled.hpt

This is the scan file from the above tune with insanely harsh 2-3 upshift.

1.hpl

This is my current tune with TM "Enabled" for upshift, but not doesn't shift well, feels like a dead spot when I shifts.

Andrew's 2016 Sierra NEW TUNED.hpt

[santeegreen]

Another scan just after reflashing and resetting trans adapt in the scanner.

2.hpl

[Ripptide56]

I'm having the same problem with my 15 Silverado. I'm going to play around with it this weekend and see if I can figure it out.

[santeegreen]

I'm having the same problem with my 15 Silverado. I'm going to play around with it this weekend and see if I can figure it out.

I re enabled all TM in the transmission settings, used a few different people tunes through the search function as a reference for volume presets and pressure and what not, just flashed it and performed the scanner transmission resets and we will see how it does over time. I know it likes to shift super weird after making changes like these but it may turn out alright. I?ve literally purchased expensive tuning guides from very reputable companies, and I just can?t seem to get anywhere with this trans. I have a feeling it?s the fact that I have 35? tires and didn?t changes gears. It?s not like I have anything crazy done on the truck.

But yeah let me know. Do you mind posting your tune? What?s your setup and what changes did you make to get the firm shift?

[santeegreen]

I?m used to tuning the 4L60?s, and apparently taking TM out of these 6L80/90?s isn?t the thing to do. I?ve been fighting this harsh shift for quite some time and it?s getting old

[Ripptide56]

I'll post it up this evening. I purchased the same guide to tune my transmission. I'm on 33's, which is not much larger than stock.

[santeegreen]

I'll post it up this evening. I purchased the same guide to tune my transmission. I'm on 33's, which is not much larger than stock.

Sounds good

[5FDP]

I pretty much never touch anything TM related with a 6L80e. I don't touch any upshift/downshift or whatever torque reduction.

I probably only changes 3-4 real settings in the calibration to make the transmission shift quicker and firmer when I need it too.

Books are okay but after doing my own reading throughout the years and testing stuff myself, the books aren't worth the time or money.


In the trucks I never want the shift timing to be much under .3000. Any quicker and I ran into harsh shift problems while doing other pressure or preset changes. I'd move the area's where you have it at .2500 and go up to .3000. Use the shift pressure or on-coming pressure presets to fine tune the shifts.

[Ripptide56]

Heres my Tune2015 Silverado Trans Tune 1.hpt

[santeegreen]

Heres my Tune2015 Silverado Trans Tune 1.hpt

I recognize all those settings you have, we definitely referenced the same tuning guide. Honestly from what I've been experiencing the last 6 months of trying to figure out the rough shifting here and there, I can say the disabling TM is NOT helping and is what is causing the harsh shifts. I but all transmission TM back to stock settings, and now I've adjusted the oncoming and offgoing pressure presets and adjusting line pressure under pattern X with slightly better results. This new tune seems to have a bit TOO much offgoing pressure, so i'll tone that down, feels like it grabs too hard at the end of the shift. So i'll take that more down towards stock and see if she shifts better. I'll post my new tune and you can reference that if you like. Disabling TM had me running around for months and couldn't get it right. Unless someone else knows something I don't.

Andrew's 2016 Sierra NEW TUNED.hpt

[santeegreen]

Heres my Tune2015 Silverado Trans Tune 1.hpt

So I found a youtube video that goes over a lot of the 6L80/90 trans tuning, I believe I searched for "6L80 tuning" on youtube. He basically confirmed a lot of what I've been reading on these forums about the transmission. Below I my latest tune file, I have re-enabled all TM and pretty much have starting messing with the oncoming and offgoing pressure presets under TRANSMISSION-SHIFT PRESSURES-ADAPTIVE-ONCOMING/OFFGOING PRESSURE PRESETS. What a difference these adjustments make, and it reacts so different with the slightest of adjustments. Take a look at mine, copy it, use it as a base, whichever you'd like, but I got the slamming to go away for the most part. And honestly the shifts can be dialed into exactly the way I want, nice and quick, firm, and snappy like I would want. I noticed if I adjust the oncoming more than 4/5 psi on all 3 columns it would go back to slamming in that gear. Also, make sure after you flash the tune to turn key to run, engine off, and go into your scanner and hit the transmission reset/preset, it's the little green button at the top, under the transmission section, and the first two buttons are what you want to hit. I believe it resets the pressure presets. Truck will shift super weird, herky/jerky for a bit, but drive it around. I even pull over after about 5/10 minutes and turn the truck off and back on and usually it will start to settle in after a bit. Try it out and let me know.

Andrew's 2016 Sierra CURRENT_1 ONCOMING_OFFGOING.hpt

https://www.youtube.com/watch?v=1L006vkWbkQ&t=1644s

[Ripptide56]

I ended up doing a new tune. I used the BlueCat Trans Tool and and used the info in the video. The only thing I've changed so far is what I got from BlueCat and I can tell you my transmission is so much better. I'll be messing with pressures this weekend.