Knocking in Rear End of Jinma 354

[cnsJohn]

I've moved this post to the Chineese Tractor forum:

My Jinma 354 has always had a slight knock in the rear end. However, lately its been getting really loud. I can't tell if it's drive train or PTO. The knocking speeds up with the trottle and it is there regardless of whether the PTO is engaged. It only stops when the clutch is completely depressed, so it may well be PTO related. Any idea what could be causing the knock? Could it be in need of a clutch adjustment?

Just for extra info, the PTO does grind slightly when engaging; and also it does stop fully when the clutch is depressed.

Any insight is greatly appreciated.

JohnJ

 

[jimmysisson]

A little hard to tell from your description, but do you hear the noise only when the tractor is moving? How about in neutral standing still?
If the ring gear in the rear were loose, that might knock while under way. It might get worse if it got looser. It also would be weak at some points in the rotation.
How many hours?
It does sound like the clutch is not completely disengaged when you engage the PTO, or you're not waiting long enough for gears to stop. Might the pilot bushing be dry?
Jim

 

[cnsJohn]

A little hard to tell from your description, but do you hear the noise only when the tractor is moving? How about in neutral standing still?
If the ring gear in the rear were loose, that might knock while under way. It might get worse if it got looser. It also would be weak at some points in the rotation.
How many hours?
It does sound like the clutch is not completely disengaged when you engage the PTO, or you're not waiting long enough for gears to stop. Might the pilot bushing be dry?
Jim

Jim,

Thank you for the response. The noise is there even when the tractor is in neutral. The tractor only has 84 hours. but the pilot bushing could be dry, since honestly, I have not checked it and don't really know where it is. Do you know if there is a separate fill/full plug for its lube? I looked at a description of the pilot bushing at yesterdays tractors dot com, and it could well be some of the problem, since the tractor is also hard to shift if the trottle is acelerated. Let me know how I can tell if the pilot bushing is dry.

Thank you again for your help.

 

[jimmysisson]

Pilot bushing is in the flywheel, normally, at the rear end of the engine crankshaft. The front of the mainshaft of the trans rides in it. At 84 hours it should be fine, unless flooded or some such, or assembled dry. In order to lube that bushing the tractor must be split - big job.
If the pto (and the tractor) stop completely when the clutch is disengaged, I doubt the pilot bushing theory, or a sticky clutch disc theory. Have you checked for full trans/rear oil fill? There might just be some slop in the transmission idler gears or the splines where the gears move on the shafts. In that case, no big deal (with enough oil) but I'd recommend you get someone knowledgeable to listen. Best of luck.
Jim

 

[rbargeron]

A knock inside that's there all the time the clutch is out usually means a gear with damaged teeth. It may have started as one chipped gear but has gotten worse as material has worn or broken away around the damage. Is it louder with the pto under load? I hit a rock with a rotary mower once that broke a couple pto gear teeth. Ran with a knock until I replaced the gears. Not a huge repair.