Grinds when yo put in gear at first

[slammer3364]

Hi I have a Jinma 284 just started grinding when you put in gear went to adjust pedal but did not help. I do not know if it is a single stage or dual stage clutch. The manuel says it needs adjusted occasionaly. Any help or tips appreciated.I did see a video on a 254 but the tractor would not move until he adjusted it Thanks Slammer

 

[CalG]

Hi I have a Jinma 284 just started grinding when you put in gear went to adjust pedal but did not help. I do not know if it is a single stage or dual stage clutch. The manuel says it needs adjusted occasionaly. Any help or tips appreciated.I did see a video on a 254 but the tractor would not move until he adjusted it Thanks Slammer

First, I'm assuming the tractor is NOT hydrostatic, but it really doesn't matter if it has a clutch.

Many tractors do not have synchronised shifting gears inside the transmission. Cars usually do in all gears but FIRST.

SO, IF there is ANY movement of the INPUT shaft and gear relative to the OUPUT shaft and gear, there will be grinding until the gears mesh.

Consider that since you are sitting still on the tractor trying to get it into gear so you can drive off, the OUTPUT shaft is stationary.

The Engine is running, and is spinning the flywheel and clutch surface. with the clutch pedal depressed, the pressure plate is clear of the friction driven plate, but that doesn't mean the friction plate is not spinning. It doesn't take much to drag that plate round and round.. It just floats on the splined transmission input shaft .

Hmkmm... Floats on the splined input shaft.... there may be something there.... grease maybe?

Any way, The input shaft NEEDS to spin somewhat in order for the gears to find a place to mesh, but there should be no power transmitted or else the gears will clash on engagement. The clash on engagement is the grinding you hear and feel.

Some people get past the grinding by forcefully and quickly moving the gear selector so all that's noted is a single CLUNK.

Some people play around with transmission lubricant viscosity. Grinding seems to be worse in winter cold, so thinner synthetic lubes sometime help the situation.

Some people clean and lubricate the spline shaft on the clutch friction plate interface. That can be a lot of work if there isn't a handi service and inspection port somewhere in the bell housing.

I'm in the single clunk camp, But then the Hurlimann tractor has synchros all around. Call it the premium model ;-)

eta

OH! IF the tractor clutch mechanism is out of adjustment, the pedal feel will be "low", that is engagement will occur very low on the pedal stroke. close to the floorboard.

The linkage needs to be shortened.

I had to do that on the Hurlimann just today, the cable actuator had jumped it's guide, and the feel was off. While I was under there. The adjusting nut and jamb nut were repositioned to take out the slack. A couple of 10mm open end wrenches did the trick.

 

[RonMar]

A Jinma 284 has a 2 stage clutch. The upper half of the pedal travel disengages the main gearbox clutch, the lower half disengages the PTO clutch. This is so you can shift gears and move without effecting the PTO like to change tractor speed while mowing. The 284 is the same as the 254 so that video should apply.

The clutch pack is bolted to the flywheel, from the flywheel back, you have the PTO disc the PTO pressure plate, pto spring, the Main disk and the main pressure plate and spring, all of which fit into the clutch housing structure. The PTO disc connects to the splined inner output shaft that runs inside the outer main shaft, all the way thru the trans to the PTO gearbox in the back of the tractor. The main disc rides on the splines of the outer shaft that drives the main gearbox.

When you step on the pedal it works a lever on the side of the case. This lever moves a fork inside which moves a sliding bearing(throw-out bearing). That bearing then pushes on 3 levers(fingers) connected to the clutch housing that lift the main pressure plate to release the main disc. this should happen by about 1/2 of your pedal travel. if you continue to press the pedal down, the main pressure plate continues to lift, and in turn lifts the PTO pressure plate to release the PTO disc.

Two things can happen:

1. The clutch discs wear and the adjustments of fingers, fork, pedal will not allow the pressure plates to fully compress the discs and they slip, tractor wont move. if you cannot adjust it the discs need to be replaced.

2. The linkage pivots, connections, forks and bearing wear and once all the slack is taken up, the available travel is not enough to fully lift the pressure plate to free the clutch disk resulting in grinding gears... Another thing that can cause this is crap and rust in the clutch disc area that then requires extra pressure plate lift to fully release the clutch disc.

Your description sounds like 2. so you need to pull a side access cover to look at the clutch adjustment. You will need to hold the pedal in various positions to look at the main and PTO pressure plate liftoff relationships. and throw-out bearing to clutch finger gap(should be no more than 1/8" with pedal all the way up). If you have a front end loader, the loader structure is usually bolted over the left and right access holes so it will have to be removed.

You also need to look for slop at all the linkage connections. Clutch pedal pivots on a bearing and connects to a rod end(2 pivot points). Other end of rod connects to end of a lever(1 point). The other end of the lever is pinned to a rod to cause it to rotate(1 point). That rod rotates to move the forks which are pinned to it(1 point) The forks fit in a notch(1 point) on a sliding collar that holds the throw-out bearing(worn or sloppy throw-out is 1 point).

All the slop at these points must be taken up to move the throw-out bearing its 1/8 inch to even start to lift the levers. my guess is something is sloppy/broken or the gap between throw-out bearing and fingers is way more than 1/8"

I personally have had the pin fail where the lever on the side of the transmission connects to rotate that rod that runs thru the side of the case to rotate the forks/slide the throw-out bearing forward. The lever was moving, but the rod pinned inside the lever end was only rotating about 3/4 as far as the lever end was. It was very hard to see and it only takes a little slop here to completely disable the clutch. The pin had partially broke which allowed the hole to go oblong so I had to drill it all out a little and add a larger pin(think I wound up making it a 1/4" bolt)... This connection should have actually been splined and not pinned as it has a fair bit of stress/torque applied to it...