cummins repowered jeep in sand dunes

RePower Profile: Jeep UACJ-6D

“One of the easiest installs you’ll ever do,” said Christian Hazel, editor of Petersen’s 4 Wheel & Off-Road Magazine about repowering the 1971 UAJ-6D.

Once everything was in place, the Cummins R2.8 fired up on the first try and has been cruising down the road ever since. In fact, anyone curious about what it takes to install a R2.8 Turbo Diesel can check out the installation guide at

cummins diesel jeep drives down rocky pathThis patina’d Jeep has been everywhere from off-roading during Ultimate Adventure 2017 to the floor at the SEMA Show. During its numerous adventures, it has consistently averaged 22-23 mpg at highway speeds, which is especially impressive considering the beadlocks and 38-inch mud tires.

Throughout its travels, this UACJ-6D has also been a beta vehicle for the R2.8 Turbo Diesel program. As a beta vehicle for the program, it has been subjected to harsh conditions that range from high altitude to high temperatures to ensure that Cummins delivers the best quality product to customers.

Vehicle Info

  • Year: 1971
  • Make: Jeep
  • Model: UACJ-6D


  • Engine: Cummins R2.8 Turbo Diesel
  • Transmission: SM420 with Advance Adapters Ranger Overdrive
  • Transfer Case: Offroad Design Magnum Box/Ford NP205
  • Axles: Dana Ultimate Dana 60, 4.88, Eaton E-locker (front and rear)

Cooling Package

  • Charge Air Cooler: Axis Industries (11.5” X 18” x 3”)
  • Radiator: Flexalite 2 core PN 60187 ( 22” x 18.5” x 2”) – 1” spacing between CAC and Radiator
  • Fan: Motorcraft Electric 15” Fan PN F4DZ8C607C, 4000-5000 CFM (16” x 22” x 4” fan shroud with 4” spacing between fan shroud and engine)


  • Springs & Such: Skyjacker Curt LeDuc Series coilover


  • Lucky rock affixed to front bumper
  • Built by Verne Simons

Learn More About the R2.8 Turbo Diesel