BD Diesel 6.4L Tap Shifter And VVT Brake

While the 6.4L Power Stroke was virtually a home run for the Ford camp compared to its 6.0L Power Stroke predecessor, it still had its fair share of shortcomings. The addition of more emissions equipment and the Diesel Particulate Filter really hurt overall fuel economy, and design flaws in the engine have caused some issues with high-mileage durability. But when it comes to power and performance, not much comes close to the 6.4L with the addition of simple bolt-ons like an intake, exhaust and tuner (550+ rear wheel horsepower capable).

“Along with the ability to control the shift pattern manually, the Tap shifter kit has six preset shift patterns that can fine-tune the automatic’s shift schedule based on driving habits and modifications.”

While these trucks can get just about any job done without breaking a sweat, the lack of factory VVT (variable vane turbo) braking and manual control over the automatic transmission can really become apparent when towing heavy or sled pulling. To overcome these issues, BD Diesel of Abbottsford, British Columbia, developed a Tap Shifter and VVT Exhaust Brake designed to improve the towing efficiency and overall driving experience of 2008-2010 6.4L Power Strokes.

Tap shifter

In 2006 GM introduced an all-new transmission feature for the Duramax/Allison combination. The “TapShifter” allowed full manual control of the shift patterns in the automatic transmission, basically allowing the driver to override the automatic shift schedule and restrict the transmission from upshifting or downshifting by control of a +/- button located on the shift lever. This quickly became a must-have feature for diesel owners and is now a standard option in both Ram and Ford trucks.

Unfortunately, Ford didn’t start offering this until the release of the 2011 6.7L Power Stroke, leaving the 2008-2010 6.4L Power Stroke owners with the sturdy 5R110 automatic in the stone age. Watching and feeling a transmission continually hunt for gears while towing over long grades and being able to maintain a safe speed and gear while descending steep passes can get quite frustrating.

1 The new Tap Shifter and Variable Vane Exhaust Brake kits from BD Diesel are the answer to every 6.4L Power Stroke owner’s dreams. Whether being used for heavy towing or just a high-performance application that could benefit from better control of the transmission, these two systems paired together are a surefire way to improve driving experience.
2 BD Diesel engineers developed the first aftermarket Tap Shifter module for the 2008-2010 6.4L Power Stroke. The system offers five preset shift schedules to improve daily driving and towing needs along with full manual shift control when the need arises.
3 The Tap Shifter control box mounts under the dash and includes a professional-grade wiring harness to make the installation virtually plug and play. The kit will piggyback the factory OBD-II port and shift selector pigtail. There’s one wire down along the frame that will need to be spliced and tapped into the BD module.
4 The factory OBD-II port will be removed from its mounting location under the dash and plugged into the female end of the OBD-II pigtail in the BD harness. The new male end of the harness will be fastened to the stock location under the dash.
5 The plastic steering column cover needs to be removed to gain access to the factory shift selector so it can be replaced with the newer 2011+ shift lever with built-in Tap Shifter buttons. There are a few screws on the bottom panel attaching it to the column, but in order to remove the cover all together, the tilt wheel lever has to be removed. You can simply slip the rubber grommet out of place and access the T20 torx screw holding it in place.

After some extensive research and testing, a new Tap Shifter for the 6.4L Power Stroke models is now in full production. The kit includes an OE 2011 Ford shift selector with built-in +/- button, professional grade wiring harness with OE pigtail connections and a LED gear select display for the dash. Using the new BD 6.4L Tap Shifter, owners can now control upshifts 1-5 and downshifts 5-1 at their fingertips, offering better control while towing heavy or trying to keep within their max power band on the sled pull track.

Along with the ability to control the shift pattern manually, the Tap Shifter kit has six preset shift patterns that can fine-tune the automatic’s shift schedule based on driving habits and modifications. The transmission’s normal shift points can be lowered 10 percent or raised as much as 30 percent depending on the setting you select, it also offers Semi/Manual and Race/Manual modes.

When running in Semi/Manual, the transmission will not kick down to a lower gear until the vehicle starts to slow. The Race mode allows control of upshifts and torque converter lock-up via the Tow/Haul button in either fourth or fifth gear. The Tap Shifter kit will also improve the truck’s overall towing performance and engine braking when running an exhaust brake or the BD Diesel Variable Vane Turbo Brake kit.

Variable Vane Exhaust Brake

Like the factory-equipped Tap Shifters available in the newer Ford, GM and Ram trucks, variable vane turbo braking is also standard issue these days. The VVT turbo’s adjustable vanes give quick spool-up with a broad mid-range and strong top end, for great performance throughout the rpm range. Since these vanes can be closed on command electronically, they can help in restricting exhaust output on deceleration for additional engine retarding and exhaust braking.

Ford has been using variable geometry turbos since the introduction of the 6.0L Power Stroke in 2003, but didn’t start offering turbo braking until the latest 2015 6.7L Power Stroke models. Since the required mechanical pieces for turbo braking are already there in the 6.4L platform, BD engineers just had to develop the electronics to control it from inside the cab.

6 With the column cover removed, there’s just one wire connector and a T30 torx bolt holding the factory shift lever in place. Since the new shift lever is genuine Ford, it will go back in place of the stocker using the same wire connector and bolt. (If installing the BD VVT Exhaust Brake module like we are, the shift lever will piggyback both the factory and Tap Shifter harnesses.)
7 With the stock lever removed, you can see the similarities and differences. While the obvious +/- button is the biggest difference, the bend in the lever is slightly different as well, which will put the lever in a little different location. The built-in Tow/Haul button will still function like stock and allow the transmission to adjust shift pattern and converter lock-up to take better control of heavy loads when accelerating and decelerating.
8 The only real wiring required with the Tap Shifter kit happens under the truck along the transmission crossmember where the main transmission wire bundle is routed. Here, you’ll remove the factory shielding to gain access to the big bundle of wires that send all electronic signals to and from the transmission. The BD module will splice into the gray/brown tracer wire, but be sure to pay attention as there are two wires in the bundle with that color combo—one a smaller 20ga, the other a thicker 18ga wire. You’ll be tapping into the smaller of the two.
9 The Tap Shifter kit includes this handy little display to show drivers which gear has been selected while in the manual shift mode. The module will display gears 1-5 as selected by the button on the shift lever. It can be placed within easy viewing right on the dash panel behind the steering wheel using the included double-sided Velcro tape (no drilling required).

The VVT Exhaust Brake system controls the factory high-pressure turbocharger exhaust vanes on command with two performance settings, one with vane braking only and one with vane braking and a more aggressive transmission downshift strategy. Since closing the vanes will increase back pressure within the engine, by downshifting and raising engine rpm you’ll be able to maximize the back pressure (upwards of 70 psi) and gain an additional 130-retarding horsepower for slowing your load or maintaining safer speeds on long downhill grades. The system is completely plug and play with just one wire needing to be tapped in the brake pedal harness. The professional-grade wiring harness allows for easy install (less than one hour in most cases).

10 With most of the Tap Shifter installation completed, it was time to move onto the BD Diesel VVT Exhaust Brake module.
11 The VVT system is controlled in-cab with a three-position switch that can be mounted just about anywhere the owner prefers. The small bracket offers endless mounting possibilities, but directly under the steering column offered the easiest reach without being in the way or requiring any drilling. Running the switch in “off” allows the turbos to work like stock. Position One is Vane Control only for mild engine brake, while Position Two offers a Vane Control along with a more aggressive transmission downshift pattern to maximize engine braking.
12 As mentioned before, when running the BD VVT Exhaust Brake module in conjunction with the Tap Shifter module, their wiring harnesses will be plugged into each other and then piggybacked into the factory wiring harness. While it seems complicated, it really is quite simply to assemble and will work flawlessly if done correctly.


The truck used in this article is a 2008 crew cab short bed with more than 170,000 miles and running a host of aftermarket parts that include a Spartan DashDaq tuner, cold air intake, 4-inch exhaust, upgraded turbochargers and a built transmission. As a laborer in the oilfields of North Dakota, the owner definitely knows how to put his truck through its paces and gave excellent feedback on the addition of the BD Diesel Tap Shifter and Variable Vane Exhaust Brake kit.

Towing a 27-foot 9,500-lb travel trailer, the new BD VVT Brake was tested on a two-mile-long 6-percent grade located just outside of Ogden, Utah. In stock form, starting off the grade at the posted 50-mph speed limit, the truck began to gain speed less than a half-mile down the hill. While the factory Tow/Haul mode helps in these situations (thanks to a good torque converter and shift control), the truck gained momentum up to 58 mph when the driver had to start riding the brakes to keep the vehicle within the speed limit.

Once at the bottom, we returned back up the grade to test out the factory upshift pattern to see how it handled the weight and allowed the engine to work and gain speed over the hill. While it felt as if the truck could’ve run cooler EGTs and worked better holding third gear, it did shift into fourth and lug its way to the top, hazing smoke out the tailpipe with EGTs getting ever so close to the unsafe 1,350+ range.

Turning around once again, we could make a final run back down the mountainside, this time running the BD VVT Brake in Position Two. This setting gave us both turbo vane control and a more aggressive downshift pattern. Again starting off the hill at the posted 50-mph speed limit, the truck maintained 50 mph for around three-tenths of a mile (stock had gained speed up to 53 mph by this point) and then started to actually slow itself and the trailer. At the half-mile point of the 6-percent grade, the truck had downshifted and slowed to just 43 mph.

13 The VVT module will tap into the factory brake pedal wiring harness so it can receive signal from the brake pedal to know exactly when it needs to turn on or off based off of the driver’s input. There’s one wire within the harness to tap, which will be easier to access if you disconnect the harness from the pedal assembly all together.
14 With both kits installed, it was time for some real-life testing. With a 9,500-lb travel trailer in tow, the additional braking assist from the turbocharger vane control became instantly noticeable, as on most grades the factory service brakes are no longer needed to maintain speed on descent. In fact, in our 6-percent grade test, we actually had to turn the exhaust brake off due to it bringing us down to well below the posted speed limit. The addition of the Tap Shifter also makes towing over the grades easier as the driver can now select the desired gear manually.

Impressed with its performance, the driver opted to continue letting the truck do its thing and see what it was capable of. Within another half-mile it had slowed to just 35 mph. With almost a mile left in the downhill stretch, the exhaust brake had been so effective that it was turned off so the truck could get back up to the posted speed limit. On the return back up the hill, running the Tap Shifter in Semi/Manual mode, the driver could command 1-3 gears only so a higher rpm range could be run over the grade. This kept boost up and EGTs down to just 1,050 degrees over the top at the same speed as it did when running stock gear patterns.

If you own a 6.4L Power Stroke and do a lot of towing, the VVT Exhaust Brake kit will definitely aid overall control and towing performance. With first-hand testing experience showing such promising results, it can turn a treacherous downhill descent into just another Sunday drive, all while taking some of the abuse off your brake pads and rotors. As for the all-new Tap Shifter kit, whether you’re daily driving and towing or using your truck as a competition hot rod running a big single turbocharger, the control it gives you over the transmission and rpm range can really take the 6.4L’s potential to an all-new level. DW

BD Power

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