Exhaust/Engine Brake, or lack of

L

Leo

New member
Sep 22, 2021
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Maybe someone can enlighten me on the use of it.
Last pickup was a 2016 Colorado with 2.8 Diesel, loved the exhaust brake on it, it worked.

Pulling the same trailer (4500 lbs gvw) with the 2021 3.0 in the Sierra Nevadas last week
and the 2021 would gain speed going down hills that the Colorado would hold me back on.

Color me less than impressed
I have read the owner manual, tried everything that I can think of.

Can the dealer set up the brake so it will work?
 
Nope, that’s what gm refers to as the brake. I’m not sure why they even called them exhaust brakes, because it does nothing more than any gas truck I’ve ever driven. I’ve had multiple dodge Cummins with real exhaust brakes and this 3.0’s is a joke
 
What I've noticed that it will kick in when you have cruise control set to a speed. When it gets over so much over that set speed, it will kick in. I've also manually down shifted to get it to work. Probably if it's in tow/haul mode and you downshift, it kicks in.

This is my first diesel so I have nothing to compare to. I assume other diesels have a button to activate it?
 
Mooseman said:
What I've noticed that it will kick in when you have cruise control set to a speed. When it gets over so much over that set speed, it will kick in. I've also manually down shifted to get it to work. Probably if it's in tow/haul mode and you downshift, it kicks in.

This is my first diesel so I have nothing to compare to. I assume other diesels have a button to activate it?
Click to expand...
I have set the speed down to 35 mph while in tow haul like my Colorado.
speed ran up to 45 mph before I started braking.
 
CoyoteJackson said:
Nope, that’s what gm refers to as the brake. I’m not sure why they even called them exhaust brakes, because it does nothing more than any gas truck I’ve ever driven. I’ve had multiple dodge Cummins with real exhaust brakes and this 3.0’s is a joke
Click to expand...
I have to agree. I have drove many trucks with an exhaust brake.
This thing is a joke.
 
Since I have no point of reference, I can't say yea or nay about it. On my 6500# RV trailer, works well enough for me.
 
On my last 6.7 dodge Cummins, the exhaust brake was weak when I bought the truck but after deleting it, the tuner must have changed the exhaust brake too because it worked like a champ. Would be nice if gm would release an update that would make it actually work
 
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CoyoteJackson said:
On my last 6.7 dodge Cummins, the exhaust brake was weak when I bought the truck but after deleting it, the tuner must have changed the exhaust brake too because it worked like a champ. Would be nice if gm would release an update that would make it actually work
Click to expand...
I agree
 
Maybe someone can explain to me what the +/- does on the column shifter? Does a trailer have to be connected and in tow/haul mode for the manual up/down shifting of the gears? Because running with just the truck it doesn’t do s#*t.
 
You have to pull the shifter all the way down to 1 or L, whichever it is, to be able to manually shift with the +/-. It just locks out any gears above the number you put it on
 
Towing around the RV right now and it does seem a bit on the weak side for engine braking. Feels more like a gasser but I do feel it.
 
Is there any button that needs to be pushed to get the exhaust ‘brake’ or it’s automatic…?
 
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Took my rig to dealer to check on exhaust brake. They told me I did not have one.
I find that hard to believe. Called Chevy customer support, all they could do was to tell me what owners manual said.
Not Happy!
 
H82looz said:
Is there any button that needs to be pushed to get the exhaust ‘brake’ or it’s automatic…?
Click to expand...
This is what the 3.0L diesel supplement says:

Brakes
Exhaust Brake
Exhaust braking is automatically activated
when Tow/Haul Mode is selected.
It maintains the vehicle’s speed by
automatically implementing a shift pattern
that uses the engine and the transmission
to slow the vehicle. The system will
command downshifts and use the
turbocharger on the engine to reduce the
vehicle’s speed when the brake is applied.
The normal tow/haul shift pattern will
return once the vehicle is on a low grade or
when the accelerator pedal is pressed.
While in the Electronic Range Select (ERS)
Mode, grade braking is deactivated, allowing
the driver to select a range and limiting the
highest gear available. See “Manual Mode”
in the owner’s manual.
Click to expand...

So short answer, put it in tow/haul mode and touch the brakes. Manually downshifting doesn't do it.

Doesn't mention cruise control neither but it may be programmed that way. I know when I have cruise control on and it sees an involuntary increase in speed (going downhill), it will downshift to maintain the set speed. However, if I'm just using the throttle myself and I let off when going downhill, it won't downshift on its own. Haven't tried touching the brake to see if it activates downshift/engine braking.

I agree that a button would be useful instead of this rigamarole.
 
Mooseman said:
This is what the 3.0L diesel supplement says:



So short answer, put it in tow/haul mode and touch the brakes. Manually downshifting doesn't do it.

Doesn't mention cruise control neither but it may be programmed that way. I know when I have cruise control on and it sees an involuntary increase in speed (going downhill), it will downshift to maintain the set speed. However, if I'm just using the throttle myself and I let off when going downhill, it won't downshift on its own. Haven't tried touching the brake to see if it activates downshift/engine braking.

I agree that a button would be useful instead of this rigamarole.
Click to expand...
My exhaust brake works like the manual says.
Put it in tow/haul mode and tap the brake. You just have to remember to do it.
 
NW GMC said:
My exhaust brake works like the manual says.
Put it in tow/haul mode and tap the brake. You just have to remember to do it.
Click to expand...
I’ll have to try this I had decided it didn’t actually have an exhaust brake and only shifts down to try and hold back to cruise set speed.
 
HalfMax said:
I’ll have to try this I had decided it didn’t actually have an exhaust brake and only shifts down to try and hold back to cruise set speed.
Click to expand...
I agree with you.
It’s not really an exhaust brake.
I prefer to set the cruise control when going down hill towing.
 
Ya I tried the braking while in tow haul mode and it does nothing, these trucks don’t have an engine brake beyond transmission shifting down and trying to hold speed like any modern gas truck, Which does nothing with a trailer on except gain some wicked rpms going downhill. It’s a pretty big oversight on GMs part I think having had trucks with actual engine brakes.
 
HalfMax said:
Ya I tried the braking while in tow haul mode and it does nothing, these trucks don’t have an engine brake beyond transmission shifting down and trying to hold speed like any modern gas truck, Which does nothing with a trailer on except gain some wicked rpms going downhill. It’s a pretty big oversight on GMs part I think having had trucks with actual engine brakes.
Click to expand...
I have to agree with you. I don't know how GM can call this an exhaust brake.
 
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