Worn Holes May Signal Countershaft Troubles

Worn Holes May Signal Countershaft Troubles Roger Gutschmidt warns owners of Deere 9600 combines to watch for bad countershafts. Early signs include worn bolt holes in the bracket that holds the gearbox on the shaft. “When my customer brought the combine in, the bolts on the bracket were loose, and the gearbox wiggled,” says Gutschmidt. “I took it apart and pulled the shaft out about a foot. I checked the splines on the shaft and the gearbox, and everything looked fine.” After putting everything back in place, he built up the bolt holes, assuming the loose bolts were the problem. He was wrong. When the combine returned to the field, it took about five acres before the gearbox was out of control. “I told him I would fix it at no cost, but for parts,” says Gutschmidt. “I talked to a service rep, and he suggested the shaft might be bent. He advised taking it apart completely and offered to help.” This time, Gutschmidt pulled the countershaft out completely. That meant removing the large pulley on the opposite end of the shaft from the gearbox. It’s a heavy cast-iron pulley that sits on the tapered shaft. “I was using a 3/4 impact on it, and when I pounded it, it flew off like a rocket and just missed my head,” recalls Gutschmidt. “The second time, I chained it so it wouldn’t go too far.” The 16-ft. long countershaft has a 4-in. diameter at the gearbox but tapers to 3 in. at the far end. Gutschmidt figured any bend would likely be on the tapered end. Rolling it on a flat surface gave no indication of a problem. However, when he mounted it in his metal lathe with a 3 1/8 spindle bore and a large chuck, the bend was clear. As Gutschmidt turned the countershaft from slow to fast, his service technician friend looked through the spindle bore with a flashlight. “About 10 in. of the countershaft goes through the gearbox,” says Gutschmidt. “When we spun it, that end was out of round, which had put a strain on the bolts and everything else with every rotation.” Gutschmidt ordered a new shaft from A&I Parts for half the price Deere would have charged. He rebuilt the bracket and reassembled everything. When he installed new bolts through the bracket into the gearbox, he added rubber bumpers.  “I asked my combine specialist friend what would have caused the problem,” says Gutschmidt. “He said slugging the machine can do it, as can putting the separator into gear under a wide-open throttle.” Gutschmidt notes that the countershaft is really the heart of the combine. “If it isn’t working, you might as well junk the combine,” he says. “But if you can find the problem, you can fix it. If you see vibration and don’t have a turning lathe big enough, take it to your local machine shop and check for a bend.” Contact: FARM SHOW Followup, Roger Gutschmidt, Gutschmidt Manufacturing, 202 Elm St. East, Box 311, Gackle, N.D. 58442 (ph 701-269-0537).

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