Diesel Exhaust Brake

sledder · April 2, 2011

I purchased a 2011 gmc sierra .when I engage the exhaust brake at a given speed with a heavy load on the truck starts to slow down . when I apply my brakes the transmission gears down the rpms increase(of course) I apply my brakes again to keep slowing down and the transmission again gears down,RPM's really increase . I cant slow down fast enough that the RPM's don't climb as high as 4500 this as a Diesel guy all my life is extremely high. I do realize that I can use the manual settings but I feel as a owner if I use the tow haul setting this should not happen .

What do you think

JDWLT · April 2, 2011

I purchased a 2011 gmc sierra .when I engage the exhaust brake at a given speed with a heavy load on the truck starts to slow down . when I apply my brakes the transmission gears down the rpms increase(of course) I apply my brakes again to keep slowing down and the transmission again gears down,RPM's really increase . I cant slow down fast enough that the RPM's don't climb as high as 4500 this as a Diesel guy all my life is extremely high. I do realize that I can use the manual settings but I feel as a owner if I use the tow haul setting this should not happen .
What do you think

How steep a grade are you going down? Are you selecting the gear you want to be in? If you are pulling a trailer use the trailer brake control instead of the foot brake.

JDWLT · April 2, 2011

Blaine,

Check out this Allison web site.

http://www.allisontransmission.com/service...tegoryID=11#143

I was told the diesel engine has a rev limiter set at 4500 RPM. The above web site is not for the 2011 but does give some interesting information about exhaust brake and Allison transmission.

Walt

sledder · April 4, 2011

Blaine,

Check out this Allison web site.

http://www.allisontransmission.com/service...tegoryID=11#143

I was told the diesel engine has a rev limiter set at 4500 RPM. The above web site is not for the 2011 but does give some interesting information about exhaust brake and Allison transmission.

Walt

Thanks I did look for the 2011 but found no information on the rev limiter . I did find the one for the 2010 however . The thing is I was using the tow haul button but fund the manual shift to be more use full

Thanks for the input

newdude · April 6, 2011

Have you tried just one brake application and then letting the exhaust brake do the work? Multiple applies of the pedal might cause it to downshift more, thus revving the engine really high. Also the function of the brake is more aggressive while in tow/haul mode. The guys at Diesel Power magazine ended up in 2nd gear down a grade in their towing battle and had to get on the throttle to put it in 3rd. They were in tow/haul also.

Max engine speed is 3000rpm, but that may be max fueled rpm, not defueled.

sledder · April 9, 2011

Have you tried just one brake application and then letting the exhaust brake do the work? Multiple applies of the pedal might cause it to downshift more, thus revving the engine really high. Also the function of the brake is more aggressive while in tow/haul mode. The guys at Diesel Power magazine ended up in 2nd gear down a grade in their towing battle and had to get on the throttle to put it in 3rd. They were in tow/haul also.

Max engine speed is 3000rpm, but that may be max fueled rpm, not defueled.

Thanks for the info . I do find the best is with the manual selector to gear down that way you can control the RPM much easier . The one other guy that had responded to my issue had suggested to use the brake controller to slow down . I want to stress to people this should only be used for emergency and setting up your brakes . I tow every day with my truck and want to make sure everyone is safe out there .

Thanks again