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

OmniGLH

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FL335i Enthusiast

FL335i

Posted
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Never even thought about disabling the grade braking in non-tow mode. I am glad I ran across this post. I live in FL. The only time I see grade braking active is when I have the tow-haul button on and am coming down a off-ramp that is angled down pretty good. Never had it activate with the tow-haul button off. What has made my trans shift much better lately in city traffic is installing the remote spin-on filter kit with a 10 micron hydraulic filter. That's made a big difference for me driving home from work. Trans fluid has gotten much cleaner looking also.

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Geiser100 Enthusiast

Geiser100

Posted
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Tried this today on my 15 4.3. Immediate results. Funny, I never really paid much attention to the transmission behavior. Now I can feel the difference. When accelerating there is almost no hesitation or sudden rpm jump from 2nd to 3rd. Slowing down is almost seamless. Crazy...

5829BMG Enthusiast

5829BMG

Posted
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Been turning off grade brake assist all week. The trans def seems to respond better to WOT inputs. Where before It would hesitate and sometimes lug in too high a gear.

 

Still waiting to hear from Blackbear if it can be tuned out.

 

Have my fingers crossed on this. I've been doing this also to me makes a difference.

southern_sierra Enthusiast

southern_sierra

Posted
Posted

I drive in manual mode 5th most of the time because it is more responsive to me, shifts better and it stays out of AFM as long as you stay out of 6th. I tried the disabling of the grade brake in drive and it shifts more like manual mode. Grade brake is also disabled in manual mode.

Jeff5347 Enthusiast

Jeff5347

Posted
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I don't think manual mode disables grade braking. I have driven in manual mode after I put 200 miles on the truck cause I hate v4. I always had the clunk and felt like I was hooked to an anchor anytime I was slowing down. If I was slowing for a light but then got on the gas cause it went green the tranny would have no clue what gear together in. After reading this thread I starting disabling grade braking. My ritual is get in, start truck, back out of my drive way, shift to manual, upshift to 5, hold tow/haul and disable GB and then go. I've done this now for the last 200 miles. Trucks feels beautiful now. No anchor feel, knows what gear to get to after slowing, when accelerating after a light or on the highway she just goes. No searching or braking or crap. Even when I drove in manual mode before I knew about the GB it just didn't feel right. Wish it was disabled by default and we had to engage to use it

 

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5829BMG Enthusiast

5829BMG

Posted
Posted

This for the 6spd it seems to use a different shift logic when on.

 

"The Grade Braking shift modes can be activated by pressing the button on the end of the shift control lever.

 

While in Range Selection Mode, Grade Braking is deactivated allowing the driver to select a desired range of gears.

 

Grade Braking is only active while the Tow/Haul Mode is selected and you are not in the Range Selection Mode. See “Tow/Haul Mode” listed previously and Manual Mode on page 9‑41 for more information on the Range Selection Mode. Grade Braking assists in maintaining desired vehicle speeds when driving on downhill grades by automatically implementing a shift schedule that utilizes the engine and transmission to slow the vehicle. This reduces wear on the braking system and increases control of the vehicle.

 

Grade Braking monitors vehicle speed, acceleration, engine torque and brake pedal usage. Using this information, it detects when the truck is on a downhill grade and the driver desires to slow the vehicle by pressing the brake.

 

This feature is active when the exhaust brake is enabled (if equipped).

 

Also see Towing Equipment on page 9‑100 for more information."

redwngr Senior Enthusiast

redwngr

Posted
Posted

I don't think manual mode disables grade braking. I have driven in manual mode after I put 200 miles on the truck cause I hate v4. I always had the clunk and felt like I was hooked to an anchor anytime I was slowing down. If I was slowing for a light but then got on the gas cause it went green the tranny would have no clue what gear together in. After reading this thread I starting disabling grade braking. My ritual is get in, start truck, back out of my drive way, shift to manual, upshift to 5, hold tow/haul and disable GB and then go. I've done this now for the last 200 miles. Trucks feels beautiful now. No anchor feel, knows what gear to get to after slowing, when accelerating after a light or on the highway she just goes. No searching or braking or crap. Even when I drove in manual mode before I knew about the GB it just didn't feel right. Wish it was disabled by default and we had to engage to use it

 

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Grade braking does NOT work in manual mode (or as GM calls it - Range Selection Mode) Or at least it's not supposed to, according to the OM.

Jeff5347 Enthusiast

Jeff5347

Posted
Posted

Grade braking does NOT work in manual mode (or as GM calls it - Range Selection Mode) Or at least it's not supposed to, according to the OM.

I see that from reading the above post....but I notice a very big difference while in manual.

Also while in manual holding the tow button...5 secs later I get a readout that it has been disabled

 

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tnchevy Senior Enthusiast

tnchevy

Posted
Posted

Drove all weekend (about 300 miles) of mixed driving with the grade brake off and honestly I can not tell much of a difference. I think this is like the 4wd flash from last year where everybody swore the transmission shifted better after the update but that topic slowly went away.

davidio840 Enthusiast

davidio840

Posted
Posted

I see that from reading the above post....but I notice a very big difference while in manual.

Also while in manual holding the tow button...5 secs later I get a readout that it has been disabled

 

Sent from my Nexus 6P using Tapatalk

 

Agreed.. I said something about this on the first few pages. I usually drive in M5 as well unless I am going on a long trip on the highway.

 

I disabled it when I first saw this thread and do it every time I get in my truck. There IS a difference. Maybe it isn't supposed to be on, or maybe it isn't on and deactivating it changes up the configuration somehow.

zert100 Enthusiast

zert100

Posted
Posted

Drove all weekend (about 300 miles) of mixed driving with the grade brake off and honestly I can not tell much of a difference. I think this is like the 4wd flash from last year where everybody swore the transmission shifted better after the update but that topic slowly went away.

 

I didn't notice any real difference in mine either, and I agree with your statement...

BIGDOGx Senior Enthusiast

BIGDOGx

Posted
Posted

Drove all weekend (about 300 miles) of mixed driving with the grade brake off and honestly I can not tell much of a difference. I think this is like the 4wd flash from last year where everybody swore the transmission shifted better after the update but that topic slowly went away.

 

It was rather easy to feel the difference to me because with it off my truck will actually coast now and not constantly search for a gear to aid in the braking causing erratic shifting behaviors.

jamin87ss Senior Enthusiast

jamin87ss

Posted
Posted

I honestly feel a difference, it will cost now instead of lunging into a downshift, but today my engine power reduce light came on and lost all power, hope it isn't related

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