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SKU #: BUL-40420 Bully Dog GT Platinum Diesel Tuner 40420 Cummins/Duramax/PowerStroke

Purchase Bully Dog GT Platinum Diesel Tuner 40420 Cummins/Duramax/PowerStroke
    • 2001-2016 6.6L GM Duramax
    • 2003-2017 5.9L / 6.7L Dodge Ram Cummins
    • 1999-2015 Powerstroke


The GT Platinum Gauge Tuner is a vehicle engine tuner, monitor, gauge and diagnostic device all in a single unit. The GT dramatically improves the utility of several vehicle applications by providing ... read more

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The GT Platinum Gauge Tuner is a vehicle engine tuner, monitor, gauge and diagnostic device all in a single unit. The GT dramatically improves the utility of several vehicle applications by providing an increase in horsepower and torque and by improving fuel economy through better engine tuning.

  • 2013-2017 Cummins will require optional Unlock Cable
  • No 2013 Ford Cab and Chassis support

The GT monitors and displays over fifteen different vehicle parameters (PIDs) on its 2.4" color screen. It also includes the all new Driving Coach feature which teaches end users to maximize their vehicles fuel economy potential. The GT performs vehicle diagnostics by reading and erasing diagnostic trouble codes; this level of vehicle transparency isn't offered by any OEM or by any other aftermarket product.

CUSTOM TUNING - The GT Platinum also supports custom tuning for Powerstroke's! But what is the difference between custom tuning and Bully Dog's preloaded tunes?

Bully Dog's pre-loaded tunes are designed for stock or lightly modified vehicles with modifications such as cold air kits, exhaust systems, or gear ratio changes. Unfortunately, as you build your vehicle with more complex modifications such as larger turbos, bigger injectors etc; the pre-loaded tunes are simply not designed to work with these heavier modifications and a "custom tune" is required.

Custom Tunes are created by one of Bully Dog / SCT's custom tuning dealers and are specifically designed for your vehicle and its modifications. Custom Tuning dealers have complete control of your vehicles PCM using the Derive Advantage Custom Tuning software and will optimize your vehicles performance for simple add-ons such as cold air kits or for high horsepower modifications such as turbo kits and larger injectors.

Triple Dog GT Diesel Tuning Features:
Power Settings:
  • Economy/ Tow Tune 50+ horsepower
  • Performance Tune 75+ horsepower
  • Extreme Tune 100+ horsepower/200lbs.-ft torque
Other Features:
  • Safety Defueling
  • Download Features (where applicable)
  • Speed Limiter
  • Rev Limiter
  • Calibrate Speedometer
  • Transmission Tuning
  • Custom Tuning (Powerstroke Only)
Vehicle Options (where applicable)
  • Seat Belt Reminder Chime
  • Auto Door Lock
Performance Gauge Functions:
  • Real Time Fuel economy
  • Average Fuel Economy
  • Trip Fuel economy
  • Load %
  • Coolant temperature
  • Fuel rail pressure (diesel vehicles)
  • Manifold absolute pressure
  • Engine RPM
  • Speed
  • Timing position
  • Air intake temperature
  • Mass Air Flow (grams/sec.)
  • Throttle position
  • Fuel level
  • Battery voltage
  • Ambient air temperature
  • Transmission temperature
  • Pyrometer #1 & 2 optional (diesel vehicles)
  • Boost (diesel vehicles)
  • IPW: injection pulse Width (diesel vehicles)
  • Barometer (diesel vehicles)
  • Oil temperature (diesel vehicles)
  • ICP: injection control pressure (diesel vehicles)

Additional Information: Also included is a performance testing feature designed to test a vehicles performance capability on the drag strip. Couple this with the free PC analysis software and users can also determine vehicle horsepower. The GT does it all and it works on most late model diesel pickups including Dodge, Ford and GM.

Owners of the 6.7L Ford PowerStroke's, the Bully Dog GT has proven to provide MASSIVE power gains, all while maintaining all of the factory emissions equipment.

Dyno numbers have shown an improvement of 128.5 horsepower and 217.8 ft-lbs of tq.

2013-2017 GT Unlock Cable: Previous to the release of this simple to use cable, you were required to remove your PCM from the truck and send it in for modification in order to allow you to tune your Cummins, obviously leading to down time for your truck. This simple cable allows you to use a Bully Dog GT (PN: 40420) to tune your, and any other 2013-2016 Cummins that also has a GT Tuner. This is a one time use cable, thus once you've originally installed the tuner using the cable, your truck is now permanently unlocked, even if you are to return it to stock, so you can tune your buddy's truck or anyone else's (as long as they have their own GT Tuner).

  • Purchase a GT Diesel Tuner and the Cummins Unlock Cable
  • Install the GT Diesel Tuner and follow on-screen instructions
  • Install the Unlock Cable and follow on-screen instructions on the GT
  • Install Tuning from the GT Tuner
Vehicle Specific Power Gains:
2015 Cummins 6.7L
  • Stock: No Horsepower / Torque Gain
  • Tow Gains: +26HP / +8ft-lbs Torque
  • Performance Gains: +55HP / +96ft-lbs Torque
  • Extreme Gains: +97HP / +185ft-lbs Torque
2015 Duramax 6.6L LML
  • Stock: No Horsepower / Torque Gain
  • Tow Gains: +31HP / +59ft-lbs Torque
  • Performance Gains: +50HP / +91ft-lbs Torque
2015 Power Stroke 6.7L
  • Stock: No Horsepower / Torque Gain
  • Tow Gains: +20HP / +50ft-lbs Torque
  • Performance Gains: +48HP / +92ft-lbs Torque
  • Extreme Gains: +71HP / +145ft-lbs Torque
no shipping No Shipping To CA


  • SkuBUL-40420
  • ManufacturerBully Dog
  • MPN40420
  • This product will not allow for the removal or disablement of factory emissions equipment, such as EGR (Exhaust Gas Recirculation) or DPF (Diesel Particulate Filter).
  • Product is not returnable if the packaging has been opened and/or product has been installed.
  • This product will support Ram truck applications with the Aisin transmission option.


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Reviews may be edited for spelling or grammar inaccuracies and those containing profanity will be removed.

BUYER BEWARE: May not work and may damage your vehicle.
In July 2020, I purchased a Bully Dog GT Platinum Tuner for my Infinity G37x. When the product arrived, it continued to render an error code and wouldn’t install into my vehicle. After waiting for several hours for a Bully Dog / Derive Systems customer service representative, I finally was connected with customer service, who advised that their server was down. After some effort on customer service’s part, they managed to remotely connect to the tuner via a laptop and install a software update. I was told that I could now install the tuner into my car. Sadly, it still didn’t work. But worse, the tuner caused several warning lights to come on in my vehicle. The next series of calls uncovered the need to go out and buy a battery charger. It should be noted that my battery is already in good working condition. After installing the battery charger, and even getting back on with customer service (after hours of hold time), the tuner still wouldn’t install into my car. This sent me into a customer service journey case study. After over a dozen calls to customer service (several of which I wasn’t able to connect due to their phone systems not being able to handle so many customer service calls), I was told to mail the Bully Dog GT Platinum Tuner back to the company for a warranty repair. At this time, I was told there was only one other known Bully Dog / Derive Systems case with the same issue. Customer service also advised that the matter had been referred to their “Engineering Department” for resolution. Well, after mailing the tuner in and receiving a replacement, the product still didn’t work. This resulted in another series of calls to the Bully Dog / Derive Systems customer service line. After another handful of hours waiting, the technician advised that the Engineering Department was still reviewing the issue and would get back to me, but that he’d request an update from them. Over a week later, I called again. This time, I was told that the case actually hadn’t been referred to their Engineering Department and that they had several other cases of their product not working where they couldn’t find a way to make it work. Effectively, I was waiting on a call back from no one. I’m not sure if this is a problem with horrible customer service, a shoddy or otherwise dangerous product, or a combination of the two. While Auto Anything acted ethically – and promptly answered my support call – by refunding the purchase price, the response by Bully Dog / Derive Systems leaves me baffled. For a company so highly reviewed to act in such an obtuse manner just doesn’t make any sense. Worse, to lie to customers that they will fix the issue, but do nothing, leaves one to wonder if the company just had an issue here, or if they are willfully selling a product they know doesn’t work to consumers. I don’t know whether this is a matter of poor customer service, a defective product, or false advertising claims. But what I do know is that I will never purchase another Bully Dog or Derive Systems product again. I guess the final stage in this saga is looking up a repair shop to figure out how to fix the damage their product caused. Buyer beware: If you purchase this product, it may not work, and it may damage your vehicle. And if you have a problem and need technical support from Bully Dog or Derive Systems, be prepared not to be able to call because there are too many other customers seeking support, to wait for hours, and, potentially, for customer service to lie to you hoping you’ll just go away and they can pocket your money.
Great power increase!!!!
Great power increase!!!!
The increase of power is noticed, BIG TIME. V...
The increase of power is noticed, BIG TIME. Very simple installation. Worth every dollar you $pend. You won't be disappointed.
Installed on my Dodge Ram 2500, simple easy t...
Installed on my Dodge Ram 2500, simple easy to follow instructions, unlock cable a bit short for my right hand drive but tech support gave me the solution, go for it guys you will love it!
The bullydog gt really opened up the power in...
The bullydog gt really opened up the power in my 2014 Dodge Ram 2500 cummins
Verified Buyer
Great product
Great product. Simple install. Noticeable power and performance. I like the defueling, comes in handy here in Texas when it's blasted hot out and your running the heck out of the truck.
Sucks this is the only way we can unlock a Cummins ECM
I bought this with the intention to use for unlocking and keep as a digital gauge once I delete and tune the truck. I had a Edge CTS only as a monitor for my old Dmax and absolutely loved it... this thing is so small I can barely read the gauge ID's while driving. The ""graph"" is pointless and wastes half the screen. I was told that the bully dog units could disable my TPMS system since they fail to communicate with the valve stem in my aftermarket rims...it doesn't. At this point I would take DPP up on their unlock service of sending a used unit with the EFILive, or whatever tuner u go with, and have the option to return it. With the money difference b/t the Egde CTS2 and this doorstop... you may save money. Completely non-expandable also... trash!
Verified Buyer
I would buy this product again
Great product ,easy to use and install
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I have a 2016 GMC Sierra 2500 Denali HD coming at the end of the month, Will this product suit it? also will it work for offroad / race applications when Ad-blue is deleted???

Yes, this tuner will work on that truck, however this will not support off-road/race exhaust.


will this chip work on my 2012 f-550 6.7 power strock cab & chassie?

Yes, this tuner is compatible with the 2012 F-550 6.7L Powerstroke.


Hey just bought a 2014 6.7 cummins. I was told adding a programmer to a stock truck with def, def, and egr would cause issues with higher exhaust temps, making the dpf filter fill up faster. Should i worry about that or will this unit work fine on a fully stock ram? just looking for better throttle response.?

In some cases we have seen more often regen cycles and higher temps on the more aggressive tunes with emissions intact. Add more fuel and unfortunately it is the nature of the beast to regen more. The bully dog is a rather safe tuner to use I don't forsee any issues for you.


how much hp increase in a 2006 5.9 cummins?

That one will add approximately 100 extra horsepower.


Can I use the Stage 4 Performance and Economy Booster Package with the Bully Dog GT Platinum Diesel Tuner 40420? And will that bully dog package let me change the size of my tires from stock to 37""? I see that you have a combo package with all of the above but only for 2013-2016. My dodge is a 2012 3500 Dually. I also wanted to know if I purchase the stage 4 can I purchase a separate muffler just incase it's a little too loud? David?

Yes you could use a Bully Dog GT for that but not to add horsepower. We include the GT in the 2013-2016 packages because it is required to unlock the ECM so one can use the EFI to tune. Yes you can purchase a separate muffler to install in that exhaust. Should be able to remove the pipe right before the over the axle section and install the muffler there.


will this leave any files on the stock pcm so if I take it out before I go in for warranty work they wont know I have had it hooked up?

This device is not undetectable by the dealer as per it flashes the ECM. If would be an item that I would remove prior to going to the dealer. In most cases if you remove the tuner before going in, they will not necessarily know that it was installed. It is a very safe programmer to use.


If i buy the GT for my 2012 6.7 Powerstroke will i need to change my emission system? If I don't will it mess with my DPM at all in the long run? What i want to do is put a tuner on a stock pickup.?

That tuner is an emissions intact tuner that will go on a 100% stock truck.


Does it improve your MPG on a GMC LML? (not interested in HP gains but MPG improvements)?

You certainly can. They do not guarantee fuel economy but this will get the truck to a point where if drove efficiently you can see fuel economy gains.

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Bully Dog GT Platinum Diesel Tuner 40420 Cummins/Duramax/PowerStroke

Bully Dog GT Platinum Diesel Tuner 40420 Cummins/Duramax/PowerStroke

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