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exhaust brake issue

16K views 22 replies 7 participants last post by  redwngr 
#1 ·
hi all

I am wondering if anyone has had and fixed the issue of the exhaust brake just stopped working?

I have a 2015 Silverado in Australia so and live in remote part of the country.(Darwin)

I have been loving the exhaust brake and found It very affective until last week when it just stopped working, no more hiss noise when I touch the brake or lift off & decelerate, it still changes down but no exhaust brake function .
I also no its not working now because previously it made I very distinct boost "choof" noise when it was decelerating and I the got back on the gas, which no longer does.

the car has 20 000klm's on it

any help or things I could check would be appreciated.

thanks Russell
 

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#3 ·
Hi thanks for the reply and thanks for the welcome, sorry my first post is a question!

i have had it tuned since new without any trouble, i tried changing tunes today but that didn't the exhaust brake to start working again.

cheers russell
 
#4 ·
Well I am at a total loss then. This forum is super helpful and there are members here that know way more about these trucks than I do, I am sure others will chime in! Did you buy the truck there or have it shipped over? Just curious if fender light was installed by GM or if it was added for compliance after the fact. Feel free to PM me if you don't want to derail the thread.
 
#7 ·
thanks redwngr

turbo appears to be functioning correctly with no loss of power, this hiss was there very distinct up until about a week ago abd really pulled the truck up.

now it gears down but noticeably lacking slowing the truck down.

I am at a loss at the moment , there are no codes either

thanks russell
 
#11 ·
thankyou guys

I have order the manuals, your right not cheap

if I figure out whats wrong I will post, as I see some posts here where the owner may not have working exhaust brake without realizing it. ( more obvious with straight through 5 inch pipe than stock pipe)

I did a 400 mile run today and the trans is downshifting in tow mode and slowing up the vehicle, but the exhaust brake is not working .


cheers russell
 
#12 ·
Do you have a boost gauge? With the exhaust brake enabled and in tow haul. When your trans is down shifting and slowing you down are you seeing any boost px?
 
#17 ·
X2, this is why I asked the question.

I would be looking into the tune thats installed on your truck before digging around looking for a problem that may not exist. I know when people were deleting their LML's with H&S some were loosing the exhaust brake.. Just a thought.
 
#20 ·
Last seen Apr 23, 2016

Probably won't hear from him.
 
#21 ·
Well, that was anticlimactic. I was hoping for a great revelation at the end of the post. I own a 2001 LB7 and since I bought it in 2012 I've never heard anything from the turbo. I can feel it as I accelerate but certainly no whine, hiss, or other noises he talked about associated with an exhaust brake. I'm all stock though so until I do any upgrades I don't expect to hear anything. I am interested to learn more about this engine brake... I assume it's not the same function that the Allison Transmission is providing in Tow/Haul mode. Do all Duramax engines come stock with an engine brake or is that a modification that comes with the tune?
 
#22 ·
LB7 do not have an exhaust brake from the factory (no VVT). You can add one like Pacbrake or BD Diesel.
 
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