Diagnosing 4WD problems YM240D

[woolyAcres]

With the front end up in the air and 4WD NOT engaged, should both wheels turn freely? What about independently?

My driver's-side front wheel is making a clicking sound and won't turn in a full circle (by hand) when the front wheel are raised off the ground. I could probably drag it in a circle if I were to lower it to the ground and drive (forward or reverse) but I'm concerned that something is out-of-whack that I can easily repair and don't want to force it for fear of really breaking it.


Here's what happened. I've been using the FEL to move some dirt/stones. After moving several loads with no problem, I backed up to get another load, while pushing into the pile i noticed my wheels turning very sharply. I took it out of 4WD and tried to back up. Same 'clicking' of the front wheel. I used the FEL to raise it off the ground and in 2WD the driver's-side won't turn in a full circle. The passenger's-side turns freely.

Any guesses as to what's going on? Any suggestions on where to begin fixing it?

Thanks in advance.

 

[PILOON]

Normal operation with wheels raised is turn one wheel clockwise and the other will turn counter clockwise.
That confirms proper differential operation.
Your description makes me think an idler gear in the differential is damaged, or perhaps the left shaft is stripped with a piece jamming the right side linkage.

Sorry to offer bad news but think you have spit open the frt differential to get an accurate diagnosis.
Splitting is not all that complicated, just be careful and use solid stands to support the raised front end while working under there.

Fortunately there are a few good Yanmar parts suppliers here on TBN so you should be able to source parts fairly easily.

Good luck and keep us posted.

 

[winston1]

With the 4 wheel drive not engaged your symptoms would lead me toward gears in the drivers side spindle or stub axle gears or bearings. The right wheel could be turning freely back through the differenctial and the disengaged drop box. Much more trouble the the wheel ends than differentials. Also the clicking you are hearing in that wheel indicates that. I would drop the lower knuckle and have a look. This might help you. Yanmar KNuckle Seal Replacement Instructions.

 

[woolyAcres]

@Piloon, @WinstonThanks for the comments. It's not the news I was hoping for but it's pretty close to what I feared. It sounds like Winston's suggestion is a bit easier to get to so I'll probably start there. Hopefully I can look at it tomorrow. If not it could be a couple weeks. My guess is it's best to leave it where it is though moving it to someplace flatter and with some shelter sure would be nice. I'll keep you guys posted but I'm headed out of town for a couple week starting Tuesday so don't hold your breath. At least I don't have an immediate need for this tractor....Thanks.p

 

[California]

moving it to someplace flatter and with some shelter sure would be nice.

I agree moving it with damaged gears could make it worse. Could you chain the loader bucket down to a sheet of plywood, get the front tires off the ground, and toboggan that backwards back to the barn or at least to a better repair location? Steer with the brakes.

 

[woolyAcres]

I was able to get the tractor backed up onto a more level spot. Not ideal, but using the FEL I was able to raise both front tires off the ground, put it in 2WD and reverse slowly. I only had to move it about 25' in this manner.

I got the front, driver's-side wheel removed and dropped the Knuckle following Winston's post. Once the knuckle was 'on the ground' I could look at both the front drive gear and the bottom spindle gear. Both looked good. No chips, no cracks, nothing. I was kinda hoping the bearing in there would be obviously cracked with a ball loose, or jamming things. No such luck. It all looked good. The portion inside the knuckle housing seemed just fine. It spun freely and very smoothly. I don't think there's any damage there.

I jacked up the rear of the tractor and in 2WD the rear spins freely and smoothly. One tire forward, one backward everything in the rear seems fine thankfully. But the problem I was having seems in the front seems to have migrated to the passenger's side. With the driver's-side knuckle on the ground, I was unable to spin the front passenger wheel when in 4WD. I ran out of daylight to check that knuckle, but I'm starting to think Piloon diagnosed it correctly, or at least taking apart the front differential is going to be required to figure out what's going on. Before committing to that job however, I'll pull down the passenger-side knuckle just so I know what's going there and because it's not too hard. Maybe I'll get lucky and find something jammed in there....

More in a couple weeks when I get back from work travel.

Thanks

 

[winston1]

Sounds like you are on top of it. I think you are taking the right course even though you may end up taking the differential apart. You feel pretty confident the drive shaft is ok? Been several cases of the drive balls coming out. With your noise coming from the front doesn't seem likely. just putting things out there to consider.

 

[woolyAcres]

I'm finally able to get back to working on this. If I want to look at the front differential, can I simply split it there (take each half off, but with the half in one piece) or do I have to remove things piecemeal, slowly stripping it away as I get closer to the differential?

 

[winston1]

I'm finally able to get back to working on this. If I want to look at the front differential, can I simply split it there (take each half off, but with the half in one piece) or do I have to remove things piecemeal, slowly stripping it away as I get closer to the differential?

Haven't been there, done that, but, just looking at part drawings would indicate you can do that. However, that axle and knuckle is going to be heavy so be sure and support it well. Looks like the splined axle shaft should slide right out of the differential. Don't go to the bank on my advice, basing this solely on what the drawings indicate.

Evidently you are confident your problem is not in the drive shaft area?

 

[woolyAcres]

@winston1- I missed the notification about your post but I can say after 'being there, doing that' that you are correct.

I've pulled everything to the driver's side of the front differential off (in pieces). I think I know that the problem is but still don't have a solution for it. Here are some photos of the progress. Referring to Hoye's parts page..
I managed to get to get the 4WD spindle (#44) but I cannot get the bottom spindle gear (#53), the Bearing (#58) or the top spindle gear (52) to come down out of there.

Now that the spindle is out of there, I can reach in from 'above' and tap it downward, which is what I started doing but it really seems stiff and I'm afraid of what I might damage trying to drive that spindle-bearing-spindle assembly downward. The snap ring (#28) is out, as are parts 47, 48, 49, 50, 51. The spindle (44) and associated parts came out the top.

At this point I know I need to replace the top seal and bearing (59 and 28). They got damaged on removal. I'm hoping the bottom and top spindle gears are okay, but they are absolutely frozen. I can not rotate the bottom spindle. No way, no how. Which is why I'm trying to get those out.

Any ideas on getting those down out of the housing?

Thanks

The first photo (the one of the spindle bearing and greasy fingers) was taken before I got the spindle etc removed.

 

[winston1]

The bottom gear #53 has outer splines that go through top gear #52. There is a snap ring #54 that holds the two gears sandwitched on the bearing #58. Can you remove the snap ring #54 and allow the two gears to come out? This will allow you to tap better on the bearings.

 

[woolyAcres]

Hi Winston-

Thanks for your response. I wish I had a photo but I don't at the moment. I don't think I can get to the snap ring (54). The whole assembly is still stuck inside the housing and I don't think I can reach through the top (where the spindle (44) has been removed). But I will have a look. I'll try to get a photo to explain this.

It seems to me the whole assembly (52; 58; and 53) should all slide out the bottom of the "housing". Based on the diagram, that's all that's left in there.

 

[woolyAcres]

Alright. Here are some photos to show where things stand. The only path forward that I can see is to continue tapping the top gear-spindle-bottom gear assembly downward. I can fit a large socket into the top opening and hold the whole thing in a vice, but movement this way is very slow and I fear I'm bumping up against something and might break something. But I do believe this whole thing should 'slide' out (with some convincing). Is that correct?

Thanks,

 

[winston1]

I do not know, is the top gear diameter smaller or larger than the bottom bearing? If diameter is smaller it should go down through the bearing opening. If not, that snap ring that holds the two gears together will have to come off. I really don't understand why I can't see that snap ring in your second picture. Seems to me it should be visible. You can see the groove here that it should be in. SPINDLE GEAR (BOTTOM) _: Yanmar Tractor Parts

 

[woolyAcres]

Hi winston-

Both the top and bottom gears are smaller than the bearing. Unfortunately the photo doesn't show it but the snap-ring on the top gear is there, but I don't think I can remove it. The only access is through the top (where the spindle exited this assembly) and it's probably 4" down in there which is beyond my reach. It sure seems like the two gears are the bread and the bearing is the meat in this sandwich. I should point out that this whole thing is frozen. The gears won't turn and the bearing appears to be seized. This was the case before I started tapping on it and I believe this has been my problem from the beginning. The picture of the top gear does show the general condition- not great in there. I don't know if the top seal was leaking, or the fluid level was low somewhere in the past, but none of this will turn.

My searches haven't turned up much, but maybe I need to widen it to include comparable JD models. Doesn't the 240 have a JD cousin?

Thanks

 

[California]

JD 750 is smaller, 850 larger (same as 2610), I think both were custom-designed for Deere after 240 was already in production. There isn't a closer Deere. I have no idea if these share front axle parts with YM240.

You probably know YM2000 is the Japan-market version of YM240 but it's the only thing that is identical. So there are parts out there but Hoye etc's replica, imported, or salvage parts are a more likely source than anything Deere.

Do you have the YM240 US English shop manual? It's excellent, may cover exactly what you need to know for this project.

 

[woolyAcres]

Hi California-

Thanks for responding.

Fortunately I do have an I&T Shop Manual. It's about 60 pages and covers several different models, the YM240D being one of them. It's great for the exploded diagrams and other specs, but I haven't found anything regarding getting these two gears and one bearing out.

I'll see what I can figure out tomorrow.

 

[California]

The service manual specifically for Yanmar YM240 alone, published by Yanmar USA, has instructions for the dealer's mechanics covering everything. It's much more comprehensive than the I&T manual which seems to be for an experienced mechanic who works on a different model every day and needs only torque, capacities, etc.

Just now I couldn't find anyone selling the genuine Yanmar-USA service manual. Here's a listing but it was in 2010. Or watch on Ebay. Hoye's version might be an identical reprint but you will need to ask them that.

 

[winston1]

If the bearing is locked up it is possible the outer race has turned in the housing causing it to be much more difficult to remove. Just from where I am sitting I would consider a large piece of hardwood that would barely fit through that top opening and a large hammer.

Ideally would be to separate the two gears but if the snap ring cannot be removed then I don't see any other choices.

 

[woolyAcres]

@winston1- that's the situation I think I'm in. A bit of elbow grease is really the only practical way forward. I'll be as gentle as I can because those two gears are pretty expensive, but I can't put it back together the way it is....