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USD 449
Part #: BT40420

Bully Dog 40420 Triple Dog GT Platinum Diesel Downloader

1999-2016 7.3L/6.0L/6.4L/6.7L Powerstroke | 2001-2015 6.6L Duramax | 2003-2017 5.9L/6.7L Cummins*
Part #: BT40420
★★★★★ ★★★★★ 30 Reviews
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The Bully Dog GT 40420 is a performance tuner AND monitor all in one compact electronic device! Get more horsepower, torque, and increase fuel efficiency in your truck with Bully Dog’s legendary tuning. All you need to do is plug the GT Tuner into your OBDII Port and perform a simple download to the vehicles ECU.

With industry leading features such as on-the-fly power level adjustments, safety defueling, and the exclusive Driving Coach, the GT Tuner is the premiere all-in-one tuner.  The GT Tuner gives you multiple power levels so you can maximize the power and efficiency of your truck whether you’re towing, daily driving, or on the track! The GT Tuner features a full color display with multiple themes and has a day and night time driving mode, so you can always quickly and clearly monitor important vehicle parameters. In addition, the GT Tuner can be used as a diagnostic tool giving you the ability to read and clear diagnostic trouble codes. 
Bully Dog Driving Coach 
Driving Coach is a special feature designed to help drivers drive more efficiently. It coaches drivers into better driving habits by providing real time visual and audio feedback as to how efficient a driver is driving. The driving coach also provides the driver with a "grade," on how efficiently they drove during a trip. This makes driving efficiently, constructive, and fun! Drivers can use the Driving Coach to coach themselves into improved driving habits. Every driver can challenge themselves to be "The perfect driver."

Parameters Monitored With Perfornance Gauge Function:
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. Along with the following diesel specific parameters: Pyrometer #1 & 2 (optional, probe sold separately), Boost, injection pulse Width, Barometer, Oil temperature, injection control pressure

  • Increases Horsepower & Torque
  • Exclusive Driving Coach Feature 
  • All-In-One Gauge Display & Tuner
  • Universal Mounting Suction Cup Included 
  • Reads & Clears Diagnostic Trouble Codes  
  • Defueling Based On Set Safety Parameters 
  • Initiates DPF Burnoff (Most 2009+ GM / Dodge Models) 
  • Free Internet Updates 

Applications Include: 
1999-2016 F-Series 250-550 7.3L/6.0L/6.4L/6.7L Powerstroke (Excludes 2013+ Cab & Chassis & Manual Xfer Case)
1999-2005 Ford Excursion 7.3L/6.0L Powerstroke
2003-2017 Dodge Ram 2500-5500 5.9L/6.7L Cummins  (2013-2017 models require 42214 Unlock Cable, online update may be required for 2016 models.)*
2001-2015 GM 2500/3500HD 6.6L Duramax
2006-2010 GM Kodiak/Topkick 4500/5500 6.6L Duramax
2006-2014 GM Savannah/Express 2500/3500 6.6L Duramax

Note: Optional EGT Probes sold separately. See items below. 

Bully Dog GT application chart/ vehicle info sheet


  • MFG. Number 40420
  • Manufacturer Name Bully Dog Technologies
  • Shipping Weight 2.00 lb.
  • Shipping Length 13 in.
  • Shipping Width 4 in.
  • Shipping Height 10 in.
  • Fuel Type Diesel
  • UPC 681018404204
  • Prop 65 WARNING: Cancer & Reproductive Harm -


★★★★★ ★★★★★
3.4/5 Stars out of 30 Reviews
Bully dog tuner
(OR) | September 14th, 2020
I have Hurd of bad experiences Hope not so far so good
GT tuner
(Gulf coast) | September 5th, 2020
Long process to download. I can’t really tell difference between stock and extreme. Check engine light on. Support says I need to call back for help. Can schedule appt. I get to blow 4hrs of my day to wait around for someone to call me back. Was never mentioned I needed unlock cable either. Don’t waste your money.
Great Product
| May 1st, 2020
Easily to install comes with everything you need to update it and install it in your truck
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Questions and Answers

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Most Popular Questions

Is the 'Bully Dog Tuner C.A.R.B. approved? I have a 2006 Ford F-350 SD, CC, XLT, 4x4, dually, 6.0L Powerstroke Turbo Diesel, 5 spd Torqshift automatic trans, 4.10 gears front & rear, 8 ft bed w/ 2003 Lance 1161 slide in truck camper mounted in the bed. Will the Bully Dog be a help to me also? OEM tow/haul pkg & OEM truck camper pkg. Any help would be greatly appreciated. Thank you Ben Sawbridge
View Staff Answer 
For the 50-State legal GT Diesel Click here

The 50-state legal GT is essentially the same as the Bully Dog GT Diesel, but has an EO number that allows it to be installed on vehicles in California. Bully Dog's 50-State Legal GT is part of the company's commitment to compliance with legal standards. The 50-State Legal GT will be a major improvement to your vehicle with the same great features found on the GT Diesel 40420.

The Triple Dog Gauge Tuner or GT is four products in one; a vehicle engine tuner, monitor, gauge and diagnostic device all in a single unit. The GT dramatically improves the utility of your vehicle by increasing horsepower, improving fuel economy and providing a comprehensive set of monitoring features and diagnostic functions.
Can the dealer detect using the device? Will it void my warranty?
View Staff Answer 

Most dealerships have no TRUE way of telling that the truck was programmed. It is highly recommended you return your vehicle to stock prior to going to a dealer for service to avoid any hassles or complications. Void your warranty? Legally, a vehicle manufacturer cannot void the warranty on a vehicle due to an aftermarket part unless they can prove that the aftermarket part caused or contributed to the failure in the vehicle (per the Magnuson Moss Warranty Act (15 U.S.C. 2302(C)) . For best results, consider working with performance-oriented dealerships with a proven history of working with customers.

What is the 50 next to tow and 75 next to performance?
View Staff Answer 

The numbers displayed are referring to the horsepower increases associated with the settings.

Will this work with 2013 dodge cab & chassis?
View Staff Answer 

BullyDog has confirmed fitment on the RAM 2500-5500 2003-2007 5.9L’s & 2007-2014 6.7L’s. (2013-14 REQUIRES PCM UNLOCK)

XDP continues to closely monitor the COVID-19 (Coronavirus) outbreak. As an integral part of the automotive supply chain, at this point all call centers and distribution centers remain fully operational to ensure we keep vital service components flowing to vehicles used in transport of goods and emergency response. To ensure the health of our employees, families, and customers, we have made the following procedural changes:

  • UPDATE: Effective 6/1 Customer Service resumes normal business hours of M-F 8:30 – 9:00pm EST.
  • Effective 3/18 we have decided to temporarily close both of our retail stores in NJ and NV.
  • Our technical sales team remains available Mon-Fri 8:30am-9pm and Saturday 10:30am-7pm EST.
  • All employees have been encouraged to follow the CDC's recommendations at home and in the workplace.
The circumstances of this virus are fast moving, as such, we will continue to update you with any further operational adjustments as needed. As always, we value your business and appreciate your patience as we manage this situation together.
Emissions Notice

This product is not legal for sale or street use in California. Certain aftermarket products are subject to governmental emission standards regulated by the California Air Resources Board. In order for these products to be legal on a specific vehicle in California, the part number must receive a CARB Executive Order (EO) number. This number makes the part legal for use only on specific years, makes and models of vehicles. A decal with CARB EO number for these parts must be displayed in the engine bay to satisfy smog inspection requirements.