2007 - Volume #31, Issue #6, Page #39[ Sample Stories From This Issue | List of All Stories In This Issue | Print this story | Read this issue]
Truck Transmission Used To Start Dead Tractors
He didn't want to tow the tractors to start them because that requires another person, and sustained cranking can be hard on the tractor to start them.
Instead, he came up with the idea of using a 4-speed truck transmission to start dead tractors through their pto shafts. He welded a GM pickup transmission to a 3-pt. hitch frame off an old implement, then mounted the frame on the 3-pt. hitch on his 1952 Ford N tractor. The input shaft on front of the transmission was too long so he cut it down and then welded a U-joint onto it. He also mounted a big yoke on the output shaft on the back side of the transmission in order to support a 3-ft. long telescoping driveshaft. The driveshaft hooks up to the dead tractor's pto.
To start a dead tractor, he puts the transmission in reverse, hooks up the driveshaft to the dead tractor's pto, and engages the pto. The driveshaft engages the dead tractor's gearing and turns the engine over in the right direction.
"It took a lot of thinking to get it figured out. I spent a lot more time building it than I'll ever spend using it," says Randall.
The transmission's output turns in the right direction to crank the dead tractor through its pto shaft. "If I hooked up a driveshaft directly between two tractors, the problem is that it would turn in the wrong direction and ruin the engine," explains Randall.
The transmission turns the engine over only slightly faster than the starter does, so the engine doesn't spin too fast, says Randall. "The dead tractor's transmission has to be in neutral and you have to put its pto in gear in order to make this idea work. I bolted a pair of steel plates onto the transmission's bell housing to block the gearshift lever so it can't be put in any gear except neutral or reverse."
You have to use a transmission with a slow reverse and creeper gear in order to get the proper gearing, he says. "The transmission I used came off a 1970's 3/4-ton GM pickup and has a 7 to 1 reduction. The gearing on the dead tractor has a 4 to 1 ratio so it's cranking the dead tractor's engine at about 400 rpm's which is about the same speed as the starter would."
Contact: FARM SHOW Followup, Larry Randall, 26104 V Dr. North, Springport, Mich. 49284 (ph 517 857-2387; lrand @voyager.net).
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