Never owned a Cummins but theirs do work better. Remember there are two redlines on tach for duramax. One for producing power, the higher one for braking. If you really need the stopping power and have the traction, just mash harder on the brakes and the truck will down shift more aggressively and rpm's will go higher than your normal red line. And that's how it's designed to work. Pretty impressive when you top a hill and traffic is stopped on other side. I thought for sure I was going to rearend someone, but the truck and trailer came to a stop way before I thought it would.

 

Are you using the tow/haul mode when towing?

 

Yes, using Tow/Haul mode and exhaust brake together. I've had issues coming down longer straighter downhills and steeper / more twisty downhills. Just seems like my RPM consistently stays well over 4,000. I've overheated brakes and transmission fluid as well.

 

They're rated for:
Maximum Powered Speed 3450 Rpm
Maximum Braking Speed 4800 Rpm

Are you using the cruise control to tell it what speed you want it to hold at?

(and of course brake push to tell it when a slower section is encountered)

 

I use the cruise control extensively - but not on these troublesome downhill grades. The downhill that gives me the most trouble is in Colorado on State Hwy 149 between Creede and Lake City going down Slumgullion Pass. There are several turns on that stretch of road that are 15 MPH turns. I don't believe the cruise will work at that speed.

 

I agree the duramax exhaust brake is the worst of all three, the dodge is the best in my opinion. From what I have read they did improve the exhaust brake in the 2024, but only time will tell how much. I did see a 2024 Chevy on a lot on Thursday so they are coming out now.

 

Yes, from what I can gather, I believe GM has made some changes to the '24 exhaust brake - I'm just having trouble getting a firm answer as to what extent those changes improve exhaust brake performance, what changes were made, etc. Historically I've not had much success in asking for answers to questions like this at the local dealer.

 

Gale Banks has done a tear-down comparison between the 2023 and 2024 6.6L dmax engines.
Part of that explains differences in turbo, turbo variable actuator, exhaust springs, etc

2024 Duramax: Everything we know - Banks Power

 

I saw two 2024 chevys at a dealer here today, maybe you can find one by you to test drive. I know it wouldn’t be towing but maybe you could tell a difference. This is the most I’ve been able to find on it..

 

I have a '22 3500 and tow a goose with 2 trucks on it, probably totaling 17-18K behind the truck, and have been happy with the braking capability from the exhaust brake. I've pulled that trailer over the san rafael swell on I70 a couple times now and it handles the hills well. You're running heavier which could change things and in a different speed range which could change things and looking at a '24 (which I also want to play with) and that will change things too, but, my '22 is better than my '17 which was better than my '13 so chances are the '24 is going to step things up too.

 

Yes, I believe GM is making gains on their exhaust brake performance - but it would sure be nice to be able to get some type of quantifiable gain in performance over the '23 year model. The Banks video was informative. I'm going to try and find someone at the local dealer that is willing to help me run down these answers from GM. Wish me luck. I will share whatever updates I can find.

 

Fast lane truck did a towing test on a 2024 Chevy.

 

I have upgraded to the 2022 GMC 2500HD from my 2012 last August. I’ve been beyond disappointed in the exhaust brake of my new truck compared to my old one. I need to hit the brakes pretty much to the floor two to three times before the exhaust brake even wants to engage. All I had to do on my 2012 was feather the brake pedal and the exhaust brake would kick in and pending the grade would keep slowing you down until you hit the fuel again. I hope the 2024’s get better

 

Inline motors are better for this style of braking. The bore and stroke are longer making this possible. V8 Diesels have smaller bore and strokes.

 

I have a 2017 3500 DRW with the L5P Duramax. Love the truck but wished the exhaust brake was more effective at keeping my speed down and engine RPM in a reasonable range when towing my 22,000 lb trailer on steep descents. There must be something fundamentally different in the design of the Cummins exhaust brake and the one in my Duramax as I've seen how well the Cummins performs in similar situations. I'm planning to purchase a 2024 3500 dually but would sure like to hear from some of you who may know if the exhaust brake effectiveness has been improved on this new model. I see where there have been changes made to the 2024 turbo, just not sure how those changes translate into improved exhaust braking without excessive engine RPM. Appreciate your comments.

I just traded my Cummins for the 2024 Duramax 3500. The exhaust brake is very weak! Fuel mileage is half of what a Cummins is. Love the truck and it is a beast but not happy with the exhaust and fuel mileage.

 

I have had a 2014, 2020 & 2024 no improvements for 2024 it poor. the 2014 was great.

 

I had a 2015 LML and the exhaust brake is better than the one in the 2024 L5P I now own.