Question about my new 2019 Duramax

[richp]

Hi,


I'm looking for information about how the tow/haul, grade braking, and exhaust brake interact on my new truck. The owner's manual is kind of sparse.



Anyone towing with a similar setup to mine have anything they can share about how these three systems work in concert, and their own experience using them?



Thanks.


Rich Phillips

[nayther]

I've got a 2014 Duramax and my routine is to set it to tow/haul, turn on the exhaust brake and push down on the skinny pedal on the right.


Just drive it!


I had issues with a previous Duramax, got this one and tried to think I was smarter than the truck, caused a CEL to come on once when I had it in manual mode. Since then just "set it and forget it" and I'm at 172,000 miles trouble free. LOVE MY DURAMAX!

[richp]

Hi nayther,


Thanks for that.


Do you also have the grade braking feature, and if so, how does that tie into this picture?


Rich

[upflying]

You might want to check a GM website for a Duramax diesel supplement manual.
My Ram has one, I downloaded and printed all 216 pages.
It goes into detail how to own and operate the truck.

[richp]

Hi upflying,


I have the printed manuals, including the diesel supplement, and have read them.



Unless my reading and comprehension skills have seriously deteriorated, GM has been really skimpy on describing these features, and most particularly how they interact.


That's why I was hoping some GM owners with a similar setup (L5P engine with exhaust brake, grade braking, and tow/haul) could clue me in on how these three systems work for them, when towing something relatively heavy.


Rich

[aeblank]

For the most part, just use it.
Tow/haul moves the shift points (quite a bit) up.
Exhaust brake holds your speed, but does it better in tow/haul (higher RPMs for it to "work on").

Grade braking? Seems the same as the exhaust brake. Unless it's the thing that keeps you from rolling backwards on an uphill stop. In that case, it's automatic.

I toggle tow/haul on/off all the time, depending on what I'm doing. I nearly never get to use my exhaust brake. I'm too light and too flat, generally.

don't overthink it. Get out and play with it.

[Wileykid]

From what I understand the grade braking is just the computer reducing power, and shifting into a lower gear to keep the truck from unintentional accelerating.

Towing, I engage the tow/haul, and exhaust brake. Tow/haul changes the shift points, basically not allowing the tranny to shift to a lower RPM (keeping the RPM's up), which could bog down the engine when you area towing. Once you are at speed and/or good RPM, the tranny will shift to the highest it can like normal. Exhaust brake is fantastic. Need to slow down, tap the brake pedal and not only will the tranny shift down, but depending on how long you brake, the exhaust brake kicks in, and you will find yourself having to get back on the gas pedal, even going downhill.

One thing Chevy doesn't do well, is explain how everything is linked together if you are using the cruise control. The cruise control will vary the gas, tranny, and exhaust brake to maintain your speed. Actually kind of fun to watch on downhills when the exhaust brake kicks in (with the appropriate attention from you). It will keep the truck within several mph. Even when I am not towing, I will use the exhaust brake at times. One thing with the exhaust brake on a Chevy, is you can not really control how much is being applied. By using the cruise control, you can control it by varying the speed you want.

Two things to know, when the exhaust brake is used, the RPM's will be high. Second is, the Allison tranny is probably one of the best, if not the best, but it is one of the roughest shifting at times. Normal though.

[richp]

Hi Wileykid,

That was exactly the kind of info I was hoping for.

Thanks very much, and also to others who have commented.

Rich

[DouglasReid]

Originally Posted by richp

Hi,


I'm looking for information about how the tow/haul, grade braking, and exhaust brake interact on my new truck. The owner's manual is kind of sparse.



Anyone towing with a similar setup to mine have anything they can share about how these three systems work in concert, and their own experience using them?



Thanks.


Rich Phillips

Here is a forum specifically devoted to trucks like yours. There are men and women on there with an encyclopedic knowledge of it, they are happy to share!

Welcome!

https://www.duramaxforum.com

[LittleBill]

Originally Posted by Wileykid

From what I understand the grade braking is just the computer reducing power, and shifting into a lower gear to keep the truck from unintentional accelerating.

Towing, I engage the tow/haul, and exhaust brake. Tow/haul changes the shift points, basically not allowing the tranny to shift to a lower RPM (keeping the RPM's up), which could bog down the engine when you area towing. Once you are at speed and/or good RPM, the tranny will shift to the highest it can like normal. Exhaust brake is fantastic. Need to slow down, tap the brake pedal and not only will the tranny shift down, but depending on how long you brake, the exhaust brake kicks in, and you will find yourself having to get back on the gas pedal, even going downhill.

One thing Chevy doesn't do well, is explain how everything is linked together if you are using the cruise control. The cruise control will vary the gas, tranny, and exhaust brake to maintain your speed. Actually kind of fun to watch on downhills when the exhaust brake kicks in (with the appropriate attention from you). It will keep the truck within several mph. Even when I am not towing, I will use the exhaust brake at times. One thing with the exhaust brake on a Chevy, is you can not really control how much is being applied. By using the cruise control, you can control it by varying the speed you want.

Two things to know, when the exhaust brake is used, the RPM's will be high. Second is, the Allison tranny is probably one of the best, if not the best, but it is one of the roughest shifting at times. Normal though.

X2.

OP, when your exhaust brake kicks in, the mpg (Fuel economy) will go up. Just switch to MPG on your information screen and see it go as high as 99 MPG while the engine is screaming (high RPM) and doing it thing braking and slowing you down.