‘I decided to build a 4WD tractor’

Late Wendell farmer took matters into his own hands


By Bill Vossler


The 4WD tractor Alan build. Contributed photo

Have something on the farm that isn’t working quite right? Looking for a solution? Ready for a big challenge? The late Alan Adams was. Adams needed a tractor with greater speed and traction, so he decided to build one.


“Some of the machinery was getting too small for my farm,” said Alan, who farmed in the Wendell, Minn., area, “so I decided to build a 4WD tractor.”

He said they had been using Cats and other tracked tractors before that, and he figured a four-wheel-drive could go through anything he could see or work with on his farm which grew wheat, corn, barley, corn, soybeans and sugar beets.


The limiting factor was the engine in his possession, a V-6 401 cubic inch GMC motor of 180 HP which ran at 3,000 revolutions per minute. That meant the tractor had to be big--which it was, 14,500 pounds later.


Starting to Build


Alan used one-quarter-inch steel plate for the framing and housings, with the side plates for the engine weighing in at 420 pounds each, and started building the tractor from there, using parts scrounged from junk piles and used machinery lots all over the state of Minnesota.


A view from the driver’s seat of Alan’s tractor. Contributed photo

Alan said he learned as he went. Not everything worked like he wanted it to. “Originally I bought two WD-9 tractors from a tractor wrecking place to use for the rear ends for this tractor. I had to take out all the gears, and then use an outside source of power. But it didn‘t work. I used a gearbox from an Adams Road Grader, but that didn’t hold either. I went to Minneapolis and had special gears made to specifications, and electro-hardened. But they got too hard, and the teeth got busted out. So I went to my local machine shop and had a gearbox made from scratch with no gears and a triple 80 roller chain of half inch steel on it, made along with bearings and an eccentric.”


That worked well. He added that there are many holes around the outside for tightening the chain. After using the tractor to plow several thousand acres of cornstalks, Alan decided to tighten up the chain. But it wouldn‘t budge. It wouldn‘t go the next level. “The chain was as tight as the day it was put it in. It hadn’t worn out. It had its original tightness.”


The only negative to the chain was when the machine was running on the road.


“If you’re going to drive it down the road at 20 miles per hour or up to its highest of 35.8 mph, the chain will get hot because there isn’t any lubricant in it. But if you’re running it in the field 7 or 8 miles per hour, it will run all day and not bother.” It’s lowest speed is eight-tenths of a mile per hour.


Since all of the fields where the Jumbo was used were only about two and a half miles from each other, speed wasn’t a problem.


He sold parts of the pair of WD-9s so he could buy other parts for his Jumbo tractor. Other parts on the tractor came from Federal, Ford, and International Trucks. The hydraulic system is Gresen, and the power steering, identical to that used on heavy earth-moving equipment, is a Char-Lynn.

Alan Adams. Contributed photo

The original transmission was a combination of two transmissions from Clark and White trucks, a four-speed and a five speed one behind the other, which translated into 26 forward gears and 10 reverse gears.


“I soon found out that when you shifted the four speed down it tore the five speed all to pieces, so I took them both out and put in a Road Ranger ten speed from a 4 x 4 truck in it. So now I don‘t have all of those gears any more.”


Another change involved the tires.


“At first I used those WD-9 tires, which were 14 inches high, but too narrow for what we were pulling. So I split the rims in the middle and added four inches in each rim, widening them out, so now I’ve got 23.1 x 30 tires on it, better because of less soil compaction and greater traction.”


He said the tractor will pull seven 16-inch plows using 8 gallons of fuel per hour of its 140 gallon tank. The radiator holds 10 gallons of fluid.


The biggest problem in building the Jumbo, Alan said, was that they couldn’t put a cab on it because the machine was being built inside in a barn with a loft above, which was too low, though the cab was added a year later.


Almost all of the Jumbo’s operations are hydraulic, including the brakes and clutch. Two implements, like diggers or plows, could be used at the same time with a dual remote that Alan set up.

Alan said he got lots of advice from his neighbors. “They would come over and say ‘This will work’ and ‘This won’t work,’ but I discovered that most of them were the opposite. Many of the things they said wouldn’t work, did, and those they said would work, didn’t. It was all a learning experience for the builder.”


People seeing the Jumbo at shows are also amazed, crawling around on it and examining it closely and trying to determine which parts might have come from which different machinery.


Front end of the homemade tractor built by Alan Adams. Contributed photo

Alan said total cost was $3,200, “But the Jumbo compares with other four-wheel-drive tractors from major equipment manufacturers that cost over $15,000.”


After he’d finished the four-month project, a neighbor came over and rode with Alan on the first day of the Jumbo’s operation, and said, “Well, this is going to take two or three farmers to go together to keep it busy. The next year that farmer had three four-wheel-drive tractors for himself. Now it’s very common. All the farmers have four-wheel-drive tractors, and many have quad tracks.”


Though nobody ever offered to buy his Jumbo, he said a number of neighbors ended up buying four-wheel-drive tractors, perhaps influenced by his homemade machine. “Those other four-wheel-drive brands were coming out then, Steigers, Versatiles, and so on.”


No implement companies came out to look at the Jumbo, but many people from around the world did. “Right away people came from Brazil, Puerto Rico, the west coast of the U.S., and many other places, to take pictures of the Jumbo.”


The Beginning of the End


Progress finally laid the Jumbo low, Alan said. “After five years, I realized the new diesel engines had more power than gasoline engines, like the one in my tractor. So we purchased a Steiger Wildcat, but that got too small, and we followed that up with a Cougar. Today we use a 4WD IH and IH Quad Track. But building the tractor was a fun challenge. I‘m a farmer by vocation, but an engineer by avocation.”


Editor’s Note: In retirement, Alan and his wife, Ramona, lived on Stuart Lake in Otter Tail County (east of Battle Lake), and wintered at their home in Siesta Village in Weslaco Texas. Alan passed away Jan. 31, 2021.

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