Need advice with John Deere 310SE rear end problem

[enginerd]

Hello everybody. I'm new to the forum, and am hoping you guys can steer me in the right direction.

I have recently acquired a 1998 John Deere 310SE for 'light duty' personal use around the property, knowing it has an apparent problem with the rear end. I'm pretty mechanically inclined, and have a lot of experience in light mechanical and fab work, but I've never worked on heavy equipment. So, I thought it would be best to ask a few questions regarding what I might expect before I start opening things up.

Here's what it's doing...

In 4wd, the front axle has power and the backhoe will drive both forward and backward. In 2 wheel drive, the rear driveline turns, but there's no power getting to the wheels in either forward or reverse, and there's a pretty heavy clunk-clunk-clunk coming from the rear end. If I engage the diff lock in 2WD, it will power itself in reverse, but in forward it still clunks and won't move (which seems very odd to me).

Initially, I thought it might be a problem with the reverser, but since the rear driveline is actually turning, I'm assuming the problem is entirely confined to the rear end. And since it has power in reverse with the diff locked, I don't think it's a problem with either the planetaries, or the ring and pinion set. Instead, I'm leaning toward the differential itself, or maybe the diff-lock system.

I think I can get to the diff-lock system with the rear end in place, but if I have to get into the diff itself, I'm pretty sure I have to drop the whole axle... and, the backhoe won't fit through the door to get into my shop, so I'll be working on it in the yard. It would certainly be nice if I didn't have to pull the rear end out and drag it to the shop in order to fix this... But, I can if I have to.

What do you think? Am I on the right track? Have I overlooked something? Are there any quick checks I could do that could narrow down the possibilities?

Thanks for any advice.

(BTW - I do have a service manual for reference.)

 

[Tinkerer]

It sounds like it may have a broken rear axle. Raise the rear tires off the ground with the stabilizers. Put the transmission in gear with the engine running. Apply each rear brake one at a time. If the wheel without the brake on does not turn or makes horrible noises it is most likely an axle. The fact you can lock the differential and get it to move is further proof the axle is broken.

 

[enginerd]

Thanks, Tinkerer. I actually just thought of that, and was going to ask if that was a possibility. I'll definitely check it out.

 

[Deeretracks]

A 310SE doesn't have a reverser so that's not it. You have to drop the axle out to do almost anything to it. Those E models had issues with the axle retaining nut lock pin breaking and the nut backing off causing all sorts of bad things. Also many issues with people crash locking the diff lock and braking the gear or the housing. It sounds like a tear down is in order.

 

[enginerd]

Thanks for the info, Deeretracks. At this point, I'm hoping for the best, and bracing for the worst. Maybe it's 'just' a broken axle. Ha!

 

[enginerd]

Ok... I got the rear tires off and drained the oil from the rear diff. And - no surprise - there's definitely metal in the oil. Lots of metal powder when I drag my magnet through the oil, along with plenty of what appears to be bits of broken splines. So, it looks like I'm going to be dealing with some combination of planetary gears, sun shaft, and/or axles. Hopefully, that's the extent of the damage.

Any wagers?

I think I'll be able to get the axle out tonight, and can pull it apart in the next couple of days.

And, as a bonus... I snapped one of the lug bolts off while I was removing the tires. Will deal with that later...

 

[GregD1]

Bite the bullet and drop it out and tear it apart. The material that the cross was made of in the carrier housing is just one notch above a number 2 lead pencil.

 

[enginerd]

Mystery solved!

Well, I got the rear end apart today. Except for the fact that everything is so heavy, it wasn't nearly as difficult as I would have imagined. Here's what I found...

The axles, planetary sets, sun shafts, ring and pinion set, and brakes all checked out OK. That takes care of everything with splines, the big gears, and the brakes, so the only thing left was the differential. After a fight with a not-quite-correct bearing puller, I finally got the left side bearing off and split the diff to find ... this.



The large left side bevel gear (pictured) and all four smaller bevel gears are wrecked, the left side thrust washer is non-existent (I think that's the metal I found in the oil that I thought looked like splines), and the left diff housing is galled up pretty bad. I suppose it could have been a lot worse, but at least now I know what parts I need to locate.

Anybody have a good source for new or used John Deere backhoe parts?

 

[Deeretracks]

I have really good luck with the parts locator on Machinery Trader.

 

[enginerd]

Thanks for the lead. I checked them out but I couldn't find what I needed. Ended up ordering from the local dealer. They matched the prices I found online, so I ended up saving quite a bit off of their list prices. Total cost: $1775, which isn't too bad, considering the total carnage. Could have been a lot worse.

 

[GregD1]

That price include bearings seals and hard parts that got damaged ? With the damage on the gears like that the bearings can`t be much better shape.

 

[enginerd]

That price was for the bearings and damaged hard parts. It does not include the four large o-rings that seal the case, so that adds another $135 to the total. And I still need to pick up a few gallons of oil. So, including consumables (shop rags, cleaner, etc.), I'm still in for less than $2k total, which is more than I was hoping, but certainly less than it could have been.

 

[GregD1]

You have checked and replaced the o-rings for the service and park brake ? If not I strongly suggest you put them on your shopping list. Are those four o-rings worth $135 dollars if that is the only leak you have when it is all back together?

 

[enginerd]

I didn't split the park break housing, so that should be good. And I have the small o-rings for the service brakes in my shop stock, so I didn't need to order those. But I appreciate the heads up. It would definitely suck to get it all back together and have to pull it apart again because I cheaped out and reused old o-rings!

 

[GregD1]

Your park brake, do you somehow figure the brake pack didn`t get any excessive wear from all the material that got ground off those side gears ???

 

[enginerd]

Well, the park brake is still fully functional at this point. And, I don't see how it could have gotten any 'excessive' wear from the metal in the oil. It is, after all, a static system; there should never be any parts moving under load. The tractor is first stopped using the service brakes, then the park brake is applied. The park brake system isn't designed to use the friction plates to slow the motion of the tractor, like the service brakes are, only to hold the tractor in place once it's already stopped. So how would it get worn from the gear damage? Am I missing something?

 

[GregD1]

What do think the pinion bearings use for lubrication ???? Does your machine have some supernatural magnetic field they float in and never wear out ??? The back side of the brake piston is the only cavity in there not getting all that worn metal not getting circulated around the bearings and seals.
Those rear axles have enough problems without any help. Your machine, your money, have fun.

 

[enginerd]

Fair enough. I appreciate the feedback.

 

[enginerd]

It sounds like it may have a broken rear axle. Raise the rear tires off the ground with the stabilizers. Put the transmission in gear with the engine running. Apply each rear brake one at a time. If the wheel without the brake on does not turn or makes horrible noises it is most likely an axle. The fact you can lock the differential and get it to move is further proof the axle is broken.

Just for future reference... I obviously didn't have a broken axle. As far as I can tell, here's what was happening with my backhoe:

There was so much wear on the carrier that the left side bevel gear was free to move about a quarter-inch (left-to-right) in the diff carrier. And, combined with the worn out teeth on the gear itself, that was enough room to allow the side gear to slip past the center gears when the diff was unlocked. But, when the diff was locked, the side gear was forced inward, and would partially mesh with the center gears. There was apparently just enough edge remaining on the 'reverse' side of the teeth to keep it from slipping in reverse (although I never ran it this way under load). But, the 'forward' edges must have been worn off just a bit more, and therefore wouldn't catch in forward gear. So, yeah... it kind of acted like a broken axle, in that it would drive in 2WD with the diff locked. But, if that was actually the case, I don't think it would have been able to drive in reverse, either.

Just thought I'd try to account for what was happening, in case someone else has the same symptoms.

 

[enginerd]

BAAAAAAHHH!!!!!!!!!

I got the call that my parts were in, so I made the 15-mile or so run the the Deere dealer this morning to pick em up. Everything looked good, so, off I went back home. When I got home, I started taking everything out of the packages, only to find that I didn't actually have the 4 small bevel gears I ordered. Instead, I only had 3 gears and some random bearing that was packed in the same sized box. What the...? After a quick call, I have to run back to the dealer. They check it out and determine that JD did indeed ship the wrong part. So, they're getting the correct part shipped, and I get to wait, then make another run to the dealer before I can put the rear end back together. Hopefully, the right part will show up before the weekend.

Very frustrating...