The running gear of the truck is what led Diesel Power to Jim. Foregoing the peer pressure to swap a blown, gasoline-burning, big-block V-8 into the van, the practical Oldaker saw gold in the two-valve, two-stroke, Detroit Diesel 6v-71 that was already on the chassis. "We went through and cleaned up the motor and replaced anything that was melted," Jim mused. "That diesel engine was really good to us. In several years of running the truck, about the only thing we ever had to do was replace an injector, and that was at the beginning of running the truck."
The engine was not modified or hot-rodded in any way-it was bone stock. It may not have made the power that some of the blown trucks made, but it was far more reliable and maintenance-free than the competition. The transmission was another very unique part of the setup. "We ran a Fuller five-speed manual transmission, which had a Creeper gear that I never, ever used," Jim said. "Most of the time I would have the truck in Second gear. The shifter had about an eight-foot throw, so there was no way to shift the thing fast. Those two-stroke diesels rev pretty good anyway." This thing defined the word unconventional.
One would think that having a vantage point 12 feet in the air and that diesel mill humming at your feet would give Jim the feeling of invincibility. Such was not the case. "After we finished the truck, some mud boggers came to the shop and offered to pay me to go and crush some cars at one of their races," Jim explained. I had never really driven this thing yet. I had taken a ride with Bob Chandler during one of his shows, but outside of moving the truck around a little, I had never done anything with it. We get up to where the show is and I take the truck for a little drive down the road to test things out. I got the rear steering tweaked a little, and the whole truck started acting really weird. I had front and rear lockers in the truck, and it was trying to twist itself up. I let out the clutch and the shifter just jumped out of gear. This was an hour before the show, and I was pretty nervous about crushing cars."
 In the early days of monster-truck...  In the early days of monster-truck shows, instead of launching into the air, the rigs crawled on top of the cars. This was a perfect assignment for 20,000 pounds of Rollin' Thunder, which truly crushed the cars in its path. |  Touring with Rollin' Thunder...  Touring with Rollin' Thunder was a team effort. Just look at how many people it takes to change the giant wheels. Luckily, Jim Oldaker's family was along for the ride. At first, they drove behind him in a pickup, but when the sport took off, he was able to buy a tour bus for his wife and kids. |  |
Basically, in the beginning the trucks would simply creep onto a stack, or just a pair of cars in Low gear, and perhaps perch themselves on top or maybe make a couple of passes over the junkers. Speed was not a concern as much as height, weight, and overall size. Bigger was better, and Jim was just about the biggest around.
Those humble beginnings lit the fuse on the monster truck bomb that eventually saw Jim and his family traversing the country six months out of the year for the next four years. Rollin' Thunder was the runner-up at the first ever side-by-side monster-truck race. Jim and his truck were a hot commodity, so hot, in fact, that he struck a deal with Detroit Diesel/Allison for sponsorship of the truck. Jim explained, "They hired us and paid us really well to travel around and run the truck. I was actually in the process of building Rollin' Thunder II when the first lightweight racing trucks showed up on the scene. I decided that another 20,000-pound tank was not going to be of much use, so we stopped that project." The second truck was going to be Detroit-powered also, utilizing an 8v-92 backed by an Allison six-speed automatic transmission with a drop box.
"It was a pretty amazing time," Jim said. "This was an unknown commodity. No one that was doing this stuff at the time knew what was going to happen. It was a big deal to a lot of us. Once we got the first couple of shows out of the way, we had offers continuously. The traveling was the stressful part at first. I drove the rig and my wife followed me with the kids in our pickup truck. We finally bought a bus. That brought the stress level down about 10 notches!"