Extreme tiller vibration..intermittent

[Trev]

I've got a JD4300 with a JD 550 tiller. I was tilling the other day, and at the end of one pass I raised the tiller and suddenly the entire tractor began to shake badly. I mean so badly the rear fenders were flapping.

I immediately idled down and disengaged the tiller, looked carefully expecting to find about a 10 lb rock wedged in there, but there was nothing. Tried it a few more times, same thing. Then, figuring I'd need to work on it or get it serviced, I tried once more.. and it was back to normal. No vibration at all. Three of us had examined it, and we were all certain there was nothing jammed into the tines, nothing hitting (like a bent tine hitting the frame, etc.)

Now I'm trying to come up with any explanation of what might have happened. If something is going wrong, to the extent of that much vibration, I can't imagine what it might be. And then to have it cure itself, and remain cured for another half hour or so of tilling, I just can't think of anything that makes sense.

Anybody got any theories?? /forums/images/graemlins/confused.gif

Thanks!
Bob

 

[tkcomer]

Not sure if this applies to you but if I raise my tiller too high it gets to vibrating. U-joints in the driveshaft were starting to bind. That’s not uncommon on short shafts. I just don’t raise it as high. One other thing to check. Make sure the PTO shaft is not too long. I had to cut mine down a little to fit on my compact tractor. I also had to cut the shaft on my seeder. I took about 2” off of each end of the shaft on both of them.

 

[Trev]

Well, sometimes I've found a little bit of vibration when I raise it up high.. but just lowering it a bit solves that. It's just the way it came from the dealer, as far as PTO shafts and all go.. and it never did this before. And I can't stress enough how SEVERE the vibration was. Raising and lowering made no difference when that began happening.. I would run it at idle and it was shaking like mad.

Maybe a bearing is heading south?

Thanks for the thoughts!

 

[KiotiJohn]

I suggest that it's probably related to your slip clutch. When you hit the rock, the tiller slip clutch probably started doing it's job, slipping to save your tiller and PTO. I imagine that it took a bit to get seated back properly, and then ran smoothly again.

Now, if you have a shear pin instead of a slip clutch, my theory sucks!

I would make sure the SC is readjusted to make sure it's operating properly, not too tight or loose (probably would be loose if anything).

If it's too loose, you'll know pretty quickly because it will slip a lot when not necessary and get hot and wear a lot too soon.

It it's too tight, not likely, when you hit something, it won't slip and the PTO and other stuff could be damaged.
John

 

[Hooked_on_HP]

Check your ujoints. Take the PTO shaft off and rotate the ujoint in all directions to make sure you dont have one freezing up. Also make sure the shaft slides in and out easy. If that checks out ok look at the bearings that supports the shaft the tines are bolted to.Make sure you can't move the shaft up and down.

 

[Trev]

Hmm, the slip clutch eh? I'll check that out! I did hit a couple of rocks that caused it to slip.. just barely got the PTO disengaged before the engine stalled. So I would guess that it *was* adjusted about right, but it might not be anymore. The vibration problem began after hitting those rocks, too. Good theory!

Thanks!

Bob

 

[KiotiJohn]

</font><font color="blue" class="small">( Hmm, the slip clutch eh? I'll check that out! I did hit a couple of rocks that caused it to slip.. just barely got the PTO disengaged before the engine stalled. So I would guess that it *was* adjusted about right, but it might not be anymore. The vibration problem began after hitting those rocks, too. Good theory!
)</font>
If the engine was going to stall, the clutch was probably too tight. I would have someone who knows how to properly adjust it do just that. It's not rocket science to do, but if it's not done properly, the rear end of your tractor may be at stake!

Make sure that whoever does the job checks for damage to the clutch which may have been the reason it vibrated for so long after the insult.

John

 

[Trev]

Yes, when it picks up a rock and jams solid, I have about 3-5 seconds before the engine stalls. I had thought that was about right, but it sounds like it probably isn't. Fortunately my dealer has a good mechanic who goes right by my house on the way to work, so I always have him stop in when I need something checked. This is definately worth having him look at it if it might save the tractor itself. Thanks for the tips!

I keep toying with the idea that I should be pulling a small plow instead of tilling, given all the rocks that come up each year. Does anyone think that might be a better solution? I don't know what I could pull with the 4300 and R4s, but perhaps a double?

Or, maybe one of those disk things I see the big tractors pulling around here (a smaller one, of course..)

I'm open to suggestions! /forums/images/graemlins/crazy.gif

Thanks again..
Bob

 

[KiotiJohn]

Just have someone determine the proper setting for the clutch based on the HP of your tractor PTO output etc. When you hit something, just stop the PTO quickly. On my tractor as soon as I hit the clutch, the tiller stops quickly because it doesn't have the momentum of a brush hog.

I think, ideally, there should be some engine drawn down noted, but it should slip enough not to kill the engine too quickly. 5 seconds may be acceptable and would give you enough time to stop the PTO before any damage could be done. You know real quick when you hit something!

John

 

[Egon]

Morning Trev:

Anyplace there is a ujoint or bearing check for slopiness by trying to move the shafts by hand. [ shut the tractor off and leave the tiller up of course.]
Rotate the tines and listen for unusal noise and bearing play.

Make sure the drive shaft has been greased and slides freely? ?

Have the ends of the driveshaft been properly seated?

After tilling for a while feel all the bearings to see if one is hotter than normal.

If problem persists phone Uncle!?

Egon /forums/images/graemlins/grin.gif