How to: Duramax Exhaust Brake Install

Updated Feb 4, 2015

Duramax Brake Down

Dial-in exhaust braking with BD Diesel’s plug-and-play variable-vane controller; 150 retarding horsepower helps haul down heavily laden late-model GM HD diesels


Tired of eating up front disc brakes and having to lay on the brake pedal longer than you’d like when your late-model GM HD pickup is towing a big gooseneck or heavy tow-behind trailer? We have found a solution.

BD Diesel Performance ( has developed an adjustable electronic controller that greatly enhances the engine-braking power of the Duramax turbo.

The Variable Vane Brake (VVB) works with the turbocharger used in the 2004.5-newer ­Duramax engines found in the 2500/3500 HD pickups.

The VVB is really simple to install and works by developing exhaust back-pressure in the engine’s combustion chamber, which creates resistance against the piston from reaching top dead center.

We placed the BD VVB control dial in the dash for easy of use. Three stages of exhaust braking/down-shifts are available with the turn of the selector.

BD’s technology electronically closes off the turbo vanes, which creates up to 150 retarding horsepower to take some of the heat off brake pads, rotors and drums.

This added exhaust-braking force, along with more aggressive downshifts, helps slow trucks pulling trailers with surge-type brakes, and/or hauling around a lot of weight in the bed.

The system works in both “Normal,” “Manual Shift” and “Tow/Haul” driving modes, too.

BD’s wiring harness “T’s” in to the lower engine control wiring. It’s a simple plug-and-run Installation.

While in Tow/Haul mode, switch BD’s Variable Vane Brake (VVB) on and every time you let off the throttle, it will close the variable vanes in the turbo.

The VVB rotary switch offers four different positions:

Off: Lets truck work in OEM stock mode.

Level/Position 1: Closes the turbo vanes only when throttle is released.

Level/Position 2: Closes the vanes and causes a moderate down-shift when throttle is released.

Truck Supply and Outfitters’ David “Chops” Adair plugs in the harness from the VVB in-cab control switch before using a couple strips of hook-and-loop fastener to attach the BD module to a 2009 GMC Sierra 3500 HD’s auxiliary battery cover.

Level/Position 3: Closes vanes and causes an aggressive downshift when throttle is released.

So if you are tired of spending down time replacing brake rotors and pads every few months, consider beefing up that turbo to help take the load off your HD’s braking system. BD’s $895 VVB kit will pay for itself in short order.