If you tow heavy loads with a Duramax — especially in mountainous terrain or steep grades — an exhaust brake is one of the most valuable add-ons you can install. It dramatically reduces service brake wear and improves control on long descents.
WHAT AN EXHAUST BRAKE DOES
- Closes a butterfly valve in the exhaust stream to create backpressure
- This backpressure creates engine braking force — slows the truck without using service brakes
- On the Allison 1000 transmission, the engine brake can be programmed to hold gear on descents
- Greatly reduces fade and extends brake pad/rotor life on mountain passes
BENEFITS FOR DURAMAX TOWING
- Maintains speed control on long grades without riding the brakes
- Reduces brake temperature — critical when towing 15,000+ lbs
- Reduces wear on rotors, pads, and drums
- Allows the Allison to downshift and hold RPM — acts as a retarder
TYPES OF EXHAUST BRAKES
- Integrated system: Some Duramax trucks have exhaust brake integrated into the factory downpipe — activated through the dash
- Aftermarket add-on: Banks Power, Pacbrake HP625 — installed in the exhaust pipe
ALLISON TOW/HAUL MODE
- Always engage Tow/Haul mode when towing — changes shift strategy and activates some engine braking
- Combine with an exhaust brake for maximum effect
TOWING TIPS
- Keep transmission temps below 200°F — add an aux cooler if temps climb
- Use an EGT gauge to monitor exhaust temps
- Check DEF level before long towing trips