One of the benefits of a Kettering University education is its customizability. Senior Jacob Yonker, a Mechanical Engineering major, is a great example.

Not finding a senior capstone class that specifically piqued his interest, Yonker instead pursued an independent study option that essentially allowed him to convert his 1977 Chevrolet pickup into a capable off-road vehicle. The capstone portion of the transformation of the truck was completing a transfer case doubler kit, giving the truck more traction options to all four wheels.

“It is basically a retrofit of OEM components with aftermarket supplements to make my truck more capable and give it more options,” said Yonker, an Alto, Mich., native who attended Caledonia High School. “The truck is unique because it started life off as a half-ton, two-wheel drive model that was converted to a ¾-ton four-wheel drive model before I purchased it. I transition to a one-ton setup and upgraded to 37 inch tires. I also changed to a 3.73:1 gear ratio in the differentials over the 3.23 gear ratios that were being run at time of purchase. The doubler essentially allows me to choose between a final ratio of 3.73:1 and 7.46:1 at the repositioning of a lever, making it a very streetable off-road rig.”

As part of the project, Yonker had to make new drive shafts and cross-member for the truck, which his friends have nicknamed ‘The Eliminator.’ The truck now has three levers inside the cab for transfer case shifting. One controls the hi/low, while the middle and right levers control the rear and front output for both axles, making the system hi/low and double low with a ratio of 1:1, 2:1 and 4:1.

“A transfer case doubler uses the range box from a New Process model 203, and a full New Process model 205 to give more gearing options off-road,” Yonker said. “With this installed I can get 1:1, 2:1 and 4:1 gear ratios through the transfer case (most OE setups are just 1:1 and 2:1). It also allows me to run in two-wheel drive front, two-wheel drive rear and four-wheel drive for each gear range (OE does not allow for front). This is beneficial over an aftermarket unit because of price -- more than $3,000 vs. less than $1,750 depending on how much you fabricate yourself.”

The project took many hours to complete. Yonker estimates that the doubler kit alone took 60-80 hours to do all the work with supporting modifications and research. He also received help from two companies in working on the project. Off Road Design gave him a discount on parts and NuWay Tool gave him free machining on some custom parts. He knew the owner of NuWay through his co-op employment.

In order to get the truck fully running, Yonker, a former vice president of Kettering’s Off-Road Club, still needs to rebuild the carburetor. He also plans to put bigger tires on the truck, add an exo cage to keep cab space maximized, rebuild the motor, relocate more components to the back of the vehicle to better balance the overall weight of the truck and do a disc brake conversion to the rear axle with cutting brakes to control steering off-road.

Yonker noted that though the truck is unique, the doubler itself is something that could be used on some other vehicles.

“It is unique because of the method I went about building it. It is transferrable to many other trucks, usually limited by the transmission and overall length of the vehicle,” he said. “For example, it doesn’t work on newer Jeeps very easily.”

The project also has given Yonker experience in what he hopes will be a future career.

“Time permitting, I plan on starting a side job doing custom bumpers and other fabrication of heavy duty off-road components,” he said.