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

[sk]

Well I drove mine all weekend both in and out of grade braking and didn't notice a big difference. Bummer - I was hoping for better results.

[scottl1346]

went out to get gas i tried this and the shifting seems better i thought i herd a clunk but may have been the trailer hitch in the bed will post after a few days of driving.

just a update after a couple hundred miles up shifting has improved but down shifting still clunks every now and again also some times i get a weird hesitation/shake but i would say its helped some with up shifting

[No Tyme]

I hope that everyone trying this is holding the Tow/Haul button for a few seconds and confirm that they are getting the message in the DIC that the Grade Braking is disabled... The first time I tried it I did not get the message and the truck drove as usual.

 

I hope this is something that BB is able to address.

[awd_rs]

Definitely got the message on the dic ...did not get any wow this is like a new truck! ....but I can´t say it shifted bad to start with . Nothing lost nothing gained right . Must have got one of the good ones off the assembly line .

[chevyman16]

Been driving my 2014 CC std box for a couple days with grade braking off and can honestly say the truck definitely feels more confident and free ... best I can describe it. I was never completely disappointed with the way the transmission shifted, but always felt like it second guessed itself once in awhile. With grade braking off, it just wants to go. There's a spot on my way home from work where it always wanted to hang up around a turn ... drove that spot today and not anymore.

[No Tyme]

Definitely got the message on the dic ...did not get any wow this is like a new truck! ....but I can´t say it shifted bad to start with . Nothing lost nothing gained right . Must have got one of the good ones off the assembly line .

Glad to hear that. I don't intentionally increase rotation of my rear tires on a regular basis but they seemed as if they wanted to sing much easier than they normally do and I have the 3:08 rears. Even getting on it a couple of times in a 20 mile trip the average mpg eased up on the DIC almost a full 1 mpg, maybe because the truck seemed to coast longer or less restrictive.

I had my trans rebuilt, specifically 3,5,R drum replaced because of shift flares that solved that issue but even after the transfer case update (which helped a small bit) my trans shifted oddly, sometimes shifting 2 gears at once or hesitating at a shift point. I do get the occasional clunk shift on downshift: haven't spent much times with disengaging the Tow/Haul mode but my first attempt seem to show some promise.

[SNOWMAN CUSTOM BAITS]

No change for me. My trans doesn't clunk it does hunt for gears sometimes but not to bad. My main complaint is the truck doesn't coast at all. If there is any change its so small I can't tell any difference.

[winn0040]

No change for me. My trans doesn't clunk it does hunt for gears sometimes but not to bad. My main complaint is the truck doesn't coast at all. If there is any change its so small I can't tell any difference.

As a lurker I created an account solely for the reason of posting in this topic. Have been driving with grade braking off for the past week and it truly is night and day for me. No more clunking, confusion searching for gears, and when mashing the gas the slight hesitation it used to have is completely gone. I want to echo what was posted above, are you absolutely sure you hold the tow haul button long enough to disengage the grade braking? The coasting difference of my truck is extremely noticeable, which is a bit of a double edged sword sitting in traffic this wonderful road construction season.

[SNOWMAN CUSTOM BAITS]

YEP!

[awd_rs]

I don´t understand the guys that say their truck does not coast. Mine takes off like a missile down hill if I´m not riding the brakes . Even after the grade braking activates it has to downshift clear to 2nd gear to hold the truck back . Once you step on the gas pedal its back to normal . At least there´s no evidence of grade braking being active till I ride the brakes again ....Don´t know who´s right but I think if my truck was downshifting or would not coast to a stop all the time . I would visit my dealer ....Grade braking should only activate after you have been riding the brakes . Check the link below .

 

http://www.acdelcotechconnect.com/pdf/TechConnect_SepOct_2013.pdf

[OldBlue61]

I'm driving a rental '15 LT1, 5.3, 3.42, and it completely transformed the truck. It's like a different vehicle. Now, instead of hunting for the correct gear (and the weird driving sensations that come along w/ that), it knows exactly what to do depending on the pressure on the 'go' pedal. What a difference!

[aggieguy03]

I'm going to try this today, but was wondering...are you guys getting the same type of "feel" if you have 4WD? Or with leveling kits and larger tires? Just trying to see if the experience is being felt across the different trucks, or if this is helping more with stock trucks and/or 2WD trucks. I've had the clunking many times in the past, but I'm definitely most interested in the ability to coast as I can tell as soon as I'm off the gas, it's trying to slow the truck rather than let it coast to a stop.

[Retired Bob]

Lots of other info at the site referenced above:

http://www.acdelcotechconnect.com/

[richrat]

I bought my truck this past December; 2015 ext. cab 2WD, 5.3L, 3.42. I have the weird transmission shifts and sporadic shutters. At first I thought this was the transmission "learning" since I read that is the case in a different post. I now have 3,400 miles and have seen no improvements. I turned off grade braking yesterday after coming across this post and there is a huge improvement. My daily commute is 15 miles in mostly city driving. Thank you for posting, hope gm does something about it, I plan on giving them a call.

[Shu]

I'm going to try this today, but was wondering...are you guys getting the same type of "feel" if you have 4WD? Or with leveling kits and larger tires? Just trying to see if the experience is being felt across the different trucks, or if this is helping more with stock trucks and/or 2WD trucks. I've had the clunking many times in the past, but I'm definitely most interested in the ability to coast as I can tell as soon as I'm off the gas, it's trying to slow the truck rather than let it coast to a stop.

2014 DC 4x4 5.3 6 sp 3:42 with leveling kit and stock 18" wheels/tires. Definitely improved the up and down shifts timing as well as coast to brake and brake feel.