4BTJ: Oil Burnin’ and 40s Turnin’ With John’s 1998 Diesel Jeep TJPosted in Features on September 10, 2018
Four-cylinder Jeep. These aren’t typically head-turning words, but when that Jeep is painted Impact Orange and fills up at the diesel pump, you bet we’re interested. We caught up with John Reidenbach on the trail as he crawled his ’98 Jeep Wrangler TJ over some of the more challenging obstacles.
John has been through a few Jeep CJs in his wheeling days—upwards of 10. However, fond as he may have been of the leaf-sprung seven-slotters, he fell in love with the (comparatively) plush ride of the coil springs available in the TJ Wranglers. John also told us of his appreciation for diesel engines, noting the fuel economy, power, and torque of the 4BT. All it took to get his Jeep project started was a Dolly Madison bakery truck.
In order to create a canvas big enough for his plans, John placed the frame of his ’98 TJ Wrangler on the operating table. Using 3/16-inch steel plating, he added 8 inches to the frame’s front end. Back to the bakery truck. The bread-toting Chevy P30 Step-Van donated life to John’s project—its Cummins 4BT diesel engine. The heavy diesel-powered block needed support, which came in the form of 1-ton axles. John harvested the high-pinion Dana 60 from a seventh-gen Ford for the Jeep’s frontend, and 4 inches back from where the factory Dana 35 once sat, he placed a Currie RockJock 60. Adding to the list of brawny parts are the 40-inch tires, an Atlas 2 transfer case, and the proverbial silver bullet of transmissions—the NV4500 five-speed manual.
One of the few regrets John has about the project is weight. He envisions shaving off a few of the Jeep’s 5,500 pounds by building his custom parts from aluminum instead of steel. Despite its weight, John reports fuel mileage well north of 20 mpg. John happily wheels his Jeep on trails in Utah, Colorado, and New Mexico, noting that it rides better than his wife’s stock Wrangler of a similar model year.
At a Glance
Vehicle: ’98 Jeep Wrangler TJ
Owner: John Reidenbach
Stomping grounds: Kenosha, Wisconsin
Build time: 6.5 months
Engine: 3.9L Cummins 4BT turbodiesel
Transfer case(s): Advance Adapters Atlas 2
Low range ratio(s): 3.8:1
Crawl ratio(s): 97.2:1
Front axle/differential: High-pinion Dana 60 narrowed 4-in, Reid Racing knuckles, Branik Motorsports 35-spline axleshafts, stock Ford 3/4-ton disc brakes, Ford spindles, 4.56 gears/ARB Air Locker
Rear axle/differential: High-pinion full-float Currie RockJock 60, stock Ford 3/4-ton disc brakes, 4.56 gears/air-actuated OX Locker
Front: Three-link, Currie Johnny Joints and Antirock sway bar, Fox 2.5-in remote-reservoir coilovers, Eibach springs
Rear: Triangulated four-link, Currie Johnny Joints, 2.5-in remote-reservoir coilovers, Eibach springs, Fox 4-in bumpstops
Tires: 40x13.50R17LT Goodyear Wrangler MT/R
Wheels: 17x10 Raceline Monster 8-lug, aluminum
Steering: Jeep J20 pitman arm, Chevy Astro gearbox, AGR Performance Rock Ram steering system
Lighting: IPF Fat Boy bulbs
Armor: Custom front bumper, Bestop rear bumper, GenRight Corner Guards, custom 3/16-inch steel bellypan w/UHMW plastic skid, custom rear tire carrier, custom front and rear fender flares
Cool stuff: Frame extended 8-in (front); internal 1.75-inch, 0.120-wall rollcage; custom aluminum fuel tank; Warn 9.5Ti w/synthetic rope; Hi-Lift jack; AutoMeter gauges; Poly Performance coilover mounts; Optima RedTop battery; Sikkens Impact Orange paint; High Angle Driveline CV driveshafts; Holset HE341 turbocharger