4-WD Pickup Converted To 6-WD
Randy Heartt needed a bale feeding truck with lots of pulling power. He also needed a heavy duty tow truck for his fifth wheel trailer. Since his farm shop is equipped with a metal lathe and milling machines, Heartt figured he had what he needed to turn a 1990 Chevrolet 4-WD pickup into a 6-WD, all without lengthening the frame.
"I didn't want to cut the frame in case what I was trying didn't work," explains Hearrt. "I took off the box, moved the original rear axle up two feet and then mounted a new rear axle behind it. As it turned out, I didn't have to lengthen the frame at all."
What he did have to do was to cut down the fuel tank to make room to move the axle ahead. Not one to take a chance with a gas tank, Heartt recalls steaming the tank for about an hour and then air drying it before cutting.
Once he had the axles where he wanted them, he reversed the original transfer case that was bolted to the transmission. It had three U-joints on it, two facing forward and one to the rear. He connected a second transfer case for the third axle. It was from an earlier model Chevy and was designed to be driven by a short driveshaft.
"The second transfer case lets me put the third axle in or out of gear from inside the cab," explains Heartt. "I can operate with one, two or all three axles."
For suspension, he relied on a modified walking beam. He used two sets of springs from a 2-ton front axle, mounting them to the frame between the two axles. The walking beams were made from 3/8-in. thick, 4 by 2-in. steel tubing. Each mounts to the springs with rubber bushings that allow them to pivot. The axles in turn mount to the ends of the walking beams with steel and rubber bushings. The bushings allowed the axles to move up and down and a little side to side.
"The walking beams allow one wheel to go up as much as 8 in. while the other three remain on the ground," explains Heartt.
Given the walking beam design, Heartt had to find a way to secure the axles in place. His solution was to weld 3 by 2-in. rectangular tubing across the frame, centered between the two axles. He then connected the axles to the tube with truck tie rods that keep them in line.
Brake lines, including the emergency brake on the original rear axle, were retained with a third set of brake lines running to the new axle. The original box was also retained, although modified.
"I was going to put a flat deck on the truck," recalls Heartt. "Instead I got another box, cut both and welded them together to get two sets of wheel wells. That was probably more work than the mechanical work, as welding sheet metal takes a long time."
The final stage of major renovation was to put a hoist under the box. Using his lathes, he made a hydraulic cylinder that's modeled after a big truckbox hoist. Because he only had about 19 in. of room in the frame to attach it, he reduced it down by making it into a telescoping shaft that extends to a full 30 in. when raised. The rear end of the box where it pivots and the area where the hoist attaches was reinforced with 2-in. angle iron. A small pump and reservoir mounted on the frame are powered off the pickup battery.
Contact: FARM SHOW Followup, Randy Heartt, Box 7581, Statoin Main, Bonnyville, Alberta, Canada T9N 2H9 (ph 780 826-6872).
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4-WD Pickup Converted To 6-WD PICKUPS Miscellaneous 27-6-2 Randy Heartt needed a bale feeding truck with lots of pulling power. He also needed a heavy duty tow truck for his fifth wheel trailer. Since his farm shop is equipped with a metal lathe and milling machines, Heartt figured he had what he needed to turn a 1990 Chevrolet 4-WD pickup into a 6-WD, all without lengthening the frame.
"I didn't want to cut the frame in case what I was trying didn't work," explains Hearrt. "I took off the box, moved the original rear axle up two feet and then mounted a new rear axle behind it. As it turned out, I didn't have to lengthen the frame at all."
What he did have to do was to cut down the fuel tank to make room to move the axle ahead. Not one to take a chance with a gas tank, Heartt recalls steaming the tank for about an hour and then air drying it before cutting.
Once he had the axles where he wanted them, he reversed the original transfer case that was bolted to the transmission. It had three U-joints on it, two facing forward and one to the rear. He connected a second transfer case for the third axle. It was from an earlier model Chevy and was designed to be driven by a short driveshaft.
"The second transfer case lets me put the third axle in or out of gear from inside the cab," explains Heartt. "I can operate with one, two or all three axles."
For suspension, he relied on a modified walking beam. He used two sets of springs from a 2-ton front axle, mounting them to the frame between the two axles. The walking beams were made from 3/8-in. thick, 4 by 2-in. steel tubing. Each mounts to the springs with rubber bushings that allow them to pivot. The axles in turn mount to the ends of the walking beams with steel and rubber bushings. The bushings allowed the axles to move up and down and a little side to side.
"The walking beams allow one wheel to go up as much as 8 in. while the other three remain on the ground," explains Heartt.
Given the walking beam design, Heartt had to find a way to secure the axles in place. His solution was to weld 3 by 2-in. rectangular tubing across the frame, centered between the two axles. He then connected the axles to the tube with truck tie rods that keep them in line.
Brake lines, including the emergency brake on the original rear axle, were retained with a third set of brake lines running to the new axle. The original box was also retained, although modified.
"I was going to put a flat deck on the truck," recalls Heartt. "Instead I got another box, cut both and welded them together to get two sets of wheel wells. That was probably more work than the mechanical work, as welding sheet metal takes a long time."
The final stage of major renovation was to put a hoist under the box. Using his lathes, he made a hydraulic cylinder that's modeled after a big truckbox hoist. Because he only had about 19 in. of room in the frame to attach it, he reduced it down by making it into a telescoping shaft that extends to a full 30 in. when raised. The rear end of the box where it pivots and the area where the hoist attaches was reinforced with 2-in. angle iron. A small pump and reservoir mounted on the frame are powered off the pickup battery.
Contact: FARM SHOW Followup, Randy Heartt, Box 7581, Statoin Main, Bonnyville, Alberta, Canada T9N 2H9 (ph 780 826-6872).
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