Interesting... progress with odd trans behavior? (2015 6-speed)

[THEREED]

 

This is my bet.

Me too. I think grade braking system may be far more intrusive than the DIC prompt indicates. I was shocked at how much more it seemed to coast when letting off accelerator after disabling. I will try it for a few more days but I anticipate a small mpg gain that others have claimed just on my experience on the first 10 miles

[ShanesGMC]

Tried on my 2016 slt 6.2 8 speed and it definately seemed to improve the shifting. Didn't have the downshift surge or clunking like it normally does

[BIGDOGx]

Me too. I think grade braking system may be far more intrusive than the DIC prompt indicates. I was shocked at how much more it seemed to coast when letting off accelerator after disabling. I will try it for a few more days but I anticipate a small mpg gain that others have claimed just on my experience on the first 10 miles

 

Same here, i don't want to believe this is all in my head but it sure seemed to stop the bucking motion that letting off the gas use to cause most of the time and the clunk issue are less when coasting and then reapplying the throttle. Called my service writer to ask if their is a permanent kill for this feature and he and also the lead tech didn't even know this was a feature that can be turned on and off, cant fault them because neither did i lol.

[Shu]

This is one of the best tips I have read on this forum. Thank you OmniGLH. Tell your tech to recommend GM rewrite with standard for hill decent to be off and only on if the operator hold the tow button for three seconds. I drove through stop and go traffic and there was no wrong gear guesses. It always was in the correct gear for speed/rpm. The dead pedal feel at stop light take offs was gone. The coast, then back to the gas clunk was gone. I am so happy with how it feels. As someone previously posted, the truck now feels more like it has the power GM claims. I am confident my mpg will increase in the city because of this as it eliminated the dead part of the throttle pedal and allowed much more precise throttle application. Quite possibly the best post ever.

[fondupot]

I emailed Justin at Blackbear performance to see if they can disable grade brake assist by default.

[14silverado4.3]

Tag for later

[Deanjo]

Where are those lurking GM customer care people on the forums? Wish one would pipe in and say that they are reporting the issue to their engineers for a fix.

[fondupot]

Where are those lurking GM customer care people on the forums? Wish one would pipe in and say that they are reporting the issue to their engineers for a fix.

 

Don't hold your breathe, those "GM customer care" people are about as helpful as the secretary at the dealership.

[caveat71]

Holy sh!t what did I just experience. I have a few scenarios that would normally produce transmission "misses" including the clunks etc. Gear shifts were buttery smooth, deceleration didnt hunt and peck for a gear to be in. The other problem I'd have is when parking, I am on a slight incline and need to park as close to a wall as possible. Often, when tapping the gas the truck would surge forward - now I couldn't even make that happen.

 

Big question is - consider all the damage done to transmissions with this horrendous flaw...I've had some bone jarring clunks over the past two years....

[Deanjo]

 

Don't hold your breathe, those "GM customer care" people are about as helpful as the secretary at the dealership.

 

Hey don't knock the dealership secretary, I had some pretty fun nights with her.

[JacobC1983]

This didn't do much for my 8 speed unfortunately... still the common clunking.

[oneandzero]

Interesting indeed.. I didn't think the grade braking even worked. I tow an 8000lb trailer and never seen any indication on the DIC. I have a Diablo Tune with a firm shift set, will give it a try to see how it reacts.

[Stumblebumble]

2015 1/2 ton

Tried this on the way home from work Wow shifts way better and be ready on the brakes in traffic cause it don't slow itself down near as much. Doesn't search for gears or jerk near as much.

If you hit tow hall also you will the realize you have 355 hp.

[brawls]

2015 1/2 ton

Tried this on the way home from work Wow shifts way better and be ready on the brakes in traffic cause it don't slow itself down near as much. Doesn't search for gears or jerk near as much.

If you hit tow hall also you will the realize you have 355 hp.

Same result here. 2014 LT with 5.3, engine braking was noticeably reduced and the 6 speed shifting seemed much improved.

 

Thank you orginal poster!

[Trucko20]

Sorry if this is a dumb question, but if everyone is having such great results with this, why isn't the truck set up like this in the first place? Is there some kind of downside here?