05 Sierra Tow/Engine Brake issue

[welderinchrist]

I have an 05 Sierra and when towing, no matter which setting the transmission is in, when accelerating over 55mph, it feels and sounds like my engine brake is kicking in even whem travelling on flat surfaces. Can anyone offer advice on how to fix this or have any pointers if it is not in fact the engine brake kicking in?

 

[Z15]

It is a diesel, V6, V8? How much are you towing? Small boat or 15,000lb trailer with skid steer?

I helps to know the info about the vehicle.

I am not even sure a 2005 Duramaz diesel has an engine brake.

 

[welderinchrist]

It's a diesel, V8 and we're towing a medium sized camper which weighs approximately 4000 pounds. We also have electric brakes on the truck as well which was set on a low setting (about .8 or .9 when in the parking lot and barely hitting the brakes). The manual that came with the truck says it does have an engine brake, and also an Allison (not sure if thats the right spelling) transmission.

 

[GMC Customer Service]

I’m sorry to hear about this – what a strange occurrence. Do you plan on taking care of this yourself or are you going to speak with your dealership about this?

Thanks,
Laura
GMC Customer Service

 

[Z15]

When was the last time you changed the fuel filter? If its been a year and or 10,000+ miles it could be in need of changing especially if you been seeking out the lowest priced fuels. Often diesel performance problems are fuel related and owners rarely change the filter as often as they should mainly because it cost a lot.

Should always carry a spare with you.

 

[welderinchrist]

Laura, if we can determine the cause of the issue, we will bring it to the GMC dealer closest to us and have them do the work on it for us, but because it's not throwing a code, the shop said that they will need to keep it for a number of days to try to figure it out, and with the luck we have, we always bring it and it never happens again until we have the vehicle back in our possession.

Z15, I'm not sure when the last time it was changed, we bought the vehicle from someone that goes to our church and they kept it in their garage and hardly ever drove it. They had it approximately 5 years and only had 20k miles put on it. I will look into the fuel filter issue. We've only had the truck for a little over 10 months, so that could possibly be the issue. Thanks for the reply.

 

[kniki10]

Are you using crew cab or extended cab? For example for extended cab the maximum towing capacity is 7700 lbs.

 

[welderinchrist]

It's a crew cab.

@Z15, the filter had, in fact, not been changed in over a year. We brought it to the local shop and let them do it and we will see how it goes on the next trip. Hopefully the filter fixed the issue.