Lost drive to rear wheels

[itsmertc]

Any advice on how to handle this problem?
I lost the drive to my rear wheels. They still turn freely when front wheels are engaged and pulling the tractor. I did notice a couple of loud clunks before this happened.

 

[Harry in Ky]

A broken rear axle shaft can give that effect. Engaging the dif lock will often gain enough traction to get you to the barn.

 

[itsmertc]

A broken rear axle shaft can give that effect. Engaging the dif lock will often gain enough traction to get you to the barn.

thank you. Is there a way to visually confirm this.

 

[SPYDERLK]

thank you. Is there a way to visually confirm this.

1st see if it will power ahead with diff locked and w/o front wheel assist.

 

[rbargeron]

thank you. Is there a way to visually confirm this.

Assuming it's the BX22 in your profile, each rear axle is held in by a spring clip on the inner end. A broken axle may start moving out of the housing (probably leak oil as it moves past the outer seal).

Confirm that hi-lo range selector still functions normally - even if only front drive works. The problem might be in the rear pinion or differential or axles. If not a broken axle, it would be hard to pinpoint from the outside. Can you add some details about the tractor hours and what was it doing when it happened? BTW, welcome to TBN - sorry about the occasion.

 

[itsmertc]

Assuming it's the BX22 in your profile, each rear axle is held in by a spring clip on the inner end. A broken axle may start moving out of the housing (probably leak oil as it moves past the outer seal).

Confirm that hi-lo range selector still functions normally - even if only front drive works. The problem might be in the rear pinion or differential or axles. If not a broken axle, it would be hard to pinpoint from the outside. Can you add some details about the tractor hours and what was it doing when it happened? BTW, welcome to TBN - sorry about the occasion.

Hello and thanks for your reply. Yes it is a BX22 . To give a quick description, I lifted the tractor up and looked under. There doesn't seam to be any obvious parts broken. The front wheels drive. No clunking noises. The rear wheels spin freely, no noises, but the right side takes some muscle while the left side is very easy to turn. Breaks work on rear wheels. PTOs seam to spin fine.

 

[SPYDERLK]

The one that spins easy is not connected to the drive.

 

[ovrszd]

The one that spins easy is not connected to the drive.

Agreed. If so, engaging the diff lock will provide pull to one rear wheel. If engaging the diff lock still leaves both rear wheels free wheeling, then it's further in the differential.

 

[itsmertc]

Engaging the diff doesn't engage either wheel.

 

[ovrszd]

Bummer.

I can't think of anything other than the main drive to the rear axle, such as the differential, spider gears, etc.

It's unusual for the ring/pinion gears to go out without having some crunching, occasional drive, etc. Same with spider gears.

Try going to Kubota's website and search for rear axle parts. You should be able to get a schematic of the rear axle assembly. Maybe by looking at that you can educate yourself as to how it works and also look for what could be causing the freewheel.

Hopefully someone will find this thread soon that has experience with this drive system and help you out.

 

[David_Kb7uns]

Would not run it much somebody on here had a BX where the locking pin in the differential was broken loose and was floating around and got caught between one of the gears and the case and it broke a hole in the case. Taking it apart is one thing but replacing the entire case is not a good thing.

David Kb7uns

 

[rbargeron]

The attached .pdf is from the factory parts list.

Which rear wheel is more free than the other side? (left or right when sitting on the tractor) Is the difference consistent or is it affected by engagement of the differential lock?

With the rear end lifted (tractor in 2wd) does stepping on either brake cause the other side to drive?

I agree with David Kb7uns concern about avoiding more damage - test it at low rpm, low power, gradual clutch. I think its going to need to come apart anyway but it would help to figure out where to separate it. Are you thinking about doing it yourself?

 

[itsmertc]

Yes will do. Do you know of any bolt that can shear?

 

[rbargeron]

Other BX differential failures are described in this thread and other TBN threads. There are pictures of damaged parts and some disassembly pictures.

The failure theory is that engaging the differential lock on the fly can cause this carnage. Broken lock pins can wreck the spider gears, causing symptoms like you describe. In some cases the housing gets destroyed too - sounds like your housing may still be ok. Best to tear it down and fix it before further damage is done.

 

[itsmertc]

The attached .pdf is from the factory parts list.

Which rear wheel is more free than the other side? (left or right when sitting on the tractor) Is the difference consistent or is it affected by engagement of the differential lock?

With the rear end lifted (tractor in 2wd) does stepping on either brake cause the other side to drive?

I agree with David Kb7uns concern about avoiding more damage - test it at low rpm, low power, gradual clutch. I think its going to need to come apart anyway but it would help to figure out where to separate it. Are you thinking about doing it yourself?

Thanks again for your help! stepping on the breaks does not make a difference and the easier to turn wheel is on the left as I'm sitting on the tractor.

 

[itsmertc]

Does anyone know what I should expect to pay for a broken axle or to replace parts in the differential? I hate to bring it to the shop blind.

 

[ovrszd]

Impossible to guess, unless someone on here has had a similar problem, then they might get close.

Know the shop hourly rate before they start. Ask for an estimate of what it will take to disassemble enough to find the problem. Demand that no parts are committed without your prior approval. In other words, they tear it down, identify the problem, price the repair cost, then call you to talk about it. If your dealer runs a good shop, they'll do all of that anyway. But in case you don't know them that well, ask for the above.

Edit: Forgot to mention,I'm very curious, I would want to visit the shop and see it apart. That way I might educate myself about why the failure happened.

 

[rbargeron]

Does anyone know what I should expect to pay for a broken axle or to replace parts in the differential? I hate to bring it to the shop blind.

From info in the linked thread in post #14, parts could be under $500. There's a couple days pf wrenching to do so shop labor might be another $2000. (semi-educated guestimates)

 

[dodge man]

This is probably an off the wall suggestion that won't help, but I had low air in my rear tires that caused a similar issue. I have fluid in my rear tires so they didn't look flat, but the tractor wouldn't pull a hill at all. I finally found it by leaning way out from the tractor and could see the rim spinning inside the tire.

 

[rbargeron]

....... The rear wheels spin freely, no noises, but the right side takes some muscle while the left side is very easy to turn. Brakes work on rear wheels......

.......stepping on the brakes does not make a difference and the easier to turn wheel is on the left........

This indicates the differential lock and spider gears no longer function and are likely broken. There may be no serious damage to other parts. Differential failures reported by other BX owners point to the differential being the weak link rather than the axles.

The fix definitely involves some hours of work but no special tools or methods. TBN members are a great resource if you decide to tackle the job yourself. Let us know what you decide to do. Dick B