Ask The Mechanic

Grinding Those Gears

Image by Steve Thompson

Q: I have a smaller Kubota tractor with a standard transmission. The gears are grinding when I try to put it in gear. And, the higher the gear, the more difficult it is to get in gear. I can cram it into gear, but I’m afraid to put it in the garage, because, sometimes, it does not like to stop without me either shutting it off or stomping on the brakes. The model number is DT225. I thought the clutch was sticking and not releasing. We took the tractor apart and replaced the clutch and pressure plate, and cleaned the input shaft splines. The tractor still grinds when shifting gears just like it was doing. Do you have any ideas what is turning the transmission with the clutch depressed?

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A: The nose of the input shaft on the transmission on this standard shift transmission runs in a bearing in the end of the crankshaft. This “pilot” bearing centers and stabilizes the input shaft. When the clutch is depressed, and connection from the engine and transmission is broken, the input shaft must also stop turning to complete the connection. The pilot bearing in the end of the crankshaft allows the crankshaft to turn but allows the input shaft to stop when the clutch is depressed. Your problem is a sticking pilot bearing. You will need a special tool to remove it after you split the tractor again and remove the pressure plate, clutch plate and flywheel. I recommend inspecting flywheel cap screws closely for thread damage and possibly replacing with new screws. Use a thread-locking product when installing and tightening to torque specifications.

Q: I have an 8N tractor that does not have a temperature gauge. I can’t find a place to install a temp gauge on this tractor, and I’m puzzled as to why this tractor did not come with one. What is the easiest way to install a temp gauge on this tractor? If I can find a place to put it in the engine, which would be the best place to install the sending unit?

A: I don’t know why the Ford 8N and 9N did not come with a temp gauge. However, a company called Steiner (www.steinertractor.com), which deals in old tractor parts, has an adapter that fits in the middle of the top radiator hose. Simply cut a short section out of the hose, and install the adapter. The adapter is already drilled to accept a standard manual temperature gauge fitting. You will need two additional hose clamps. Pappy Thompson put one of these on his 8N, and it worked great. The front of the engine is the best place on a tractor to receive a temperature reading, because the water flows from the back of the engine to the front through the engine block and head. As the coolant moves to the front of the engine, it absorbs all the heat of the engine on its path to the top of the radiator. As this hot coolant flows through the top radiator hose, the temp-sending unit will get a reading before the coolant heads down through the radiator to be pumped back through the engine as a cooled liquid.

Safety Tip of the Month:

The largest percentage of farm accidents stems from tractor rollovers, and many older tractors did not come equipped with rollover protection structures (RPSs). The RPS works well with a seat belt to protect the operator in case of a rollover. The Journal of Agricultural Safety and Health reports that 99% of all rollover deaths on farm tractors would be eliminated with RPS and a buckled seat belt. Small, compact tractors equipped with a loader are vulnerable for a rollover because of their powerful loader hydraulics and short, narrow wheelbases. Currently, more than 40% of all tractors sold in the U.S. are around the 40-hp range and under. A tractor’s center of gravity can change very quickly with a bucket of dirt or bale of hay high in the air. If your tractor is not equipped with RPS, I suggest you install one and keep the folding type (easier to get inside a garage) pinned up, and the seat belt tightly fastened when in use.

Write Steve Thompson at Ask The Mechanic, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email mechanic@progressivefarmer.com.

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