BX24 diff lock disaster ... How many others have had this problem?

[hodge]

I doubt that Kubota designed the lock with a shear pin. That is not where a weak link would be engineered into the system. It isn't uncommon for a manufacturer to plan for breakage- on a truck, the driveshaft/universal joint is the weak link, and the cheapest to replace. Kubota wouldn't design that into the differential. Therefore, regardless of what caused the breakage, they wouldn't engineer the case to accomodate broken parts. Bad things happen. It is as simple as that. I know that I can't plan for every possible catasrophe in my work- neither can anyone on this forum, and neither can Kubota. It is real easy to blame them for specific, perceived flaws, after the fact. It is entirely another thing to plan for them ahead of time. I feel bad that it happened, but if I were Kubota, I wouldn't take the blame, either.
And, obviously, after 61 responses, not one other person has responded with the same problem- it must be an isolated incident.

 

[David_Kb7uns]

David, did you just chime in now or did you read the thread? Odds are that you CANNOT engage the diff lock at all if you are NOT spinning at least to some degree. You get 2 chances on a spin of the axle to make this happen.

This thread has been around for a while now and I don't recall the exact circumstances, but I don't believe the OP said he was at full throttle, full speed when this happened.

Engaging diff lock lever and advancing until it locks is one thing but I have seen too many people hammer it while rocking pedal back and forth. Of all the times I have gotten stuck the 4 wheel drive does much more then the differential lock in getting out.

Also have read all the wining through the thread been here all the time, there are somethings that you just can not engineering into a product. I have never heard of making space for broken pieces clearance space in the design process.

David Kb7uns

 

[LBrown59]

Quote:
Originally Posted by GolfAddict
On the way up and the way down I'll keep a gentle pressure on the locking lever with my heel. Often it will engage when the high rear wheel starts to loose a bit of traction. The lever will press down and "slip" into diff lock smoothly. So, of course, I am engaging the lock while the wheels are spinning...
didn't realize what a no-no that can be.
I am thinking I'll just use 4wd from now on.

It's right in the owners manual
so I don't know how anyone could miss it.

 

[snort]

I doubt that Kubota designed the lock with a shear pin. That is not where a weak link would be engineered into the system. It isn't uncommon for a manufacturer to plan for breakage- on a truck, the driveshaft/universal joint is the weak link, and the cheapest to replace. Kubota wouldn't design that into the differential. Therefore, regardless of what caused the breakage, they wouldn't engineer the case to accomodate broken parts. Bad things happen. It is as simple as that. I know that I can't plan for every possible catasrophe in my work- neither can anyone on this forum, and neither can Kubota. It is real easy to blame them for specific, perceived flaws, after the fact. It is entirely another thing to plan for them ahead of time. I feel bad that it happened, but if I were Kubota, I wouldn't take the blame, either.
And, obviously, after 61 responses, not one other person has responded with the same problem- it must be an isolated incident.

Hello all,

I've been following this thread and think I've read all the messages. I just bought a BX25 a few months ago. It lives in the garage with a Ford 8N which I've been using for over 30 years. I bought the Kubota because I am getting too "mature" to wrestle with a walk behind blower to clear a kilometer of driveway every time it snows (which it does a lot here in western Newfoundland). The idea of a differential lock seems great but from what I am reading in this thread, misuse of it can be very expensive. I was certainly not warned about how this pedal should be used when I bought the tractor (from Kubota dealer), nor was proper usage or any warnings given in the operator's manual. My question is: can anybody explain under what conditions can the lock be used and how should it be activated? I'm thinking to engage you should be stopped or close to it, rear tires should not be spinning, you should gently put pressure on the pedal until you feel the pin insert/seat itself, locking the differential. Once done, you need to be moving in a straight line. If you need to turn, you should take your foot off the pedal, uncoupling the pin and unlocking the differential. Appreciate it if anyone could confirm or correct my impression.

Best wishes for the new year

 

[GolfAddict]

It's right in the owners manual
so I don't know how anyone could miss it.

OK, dug my owners manual out. The entire section on the differential lock is very brief. A few appropriate safety warnings (the rear wheel are locked, so of course steering is going to be affected) followed by the operation instructions. This is the section of operating instruction verbatim:

If one of the rear wheels should slip, step on the differential lock pedal. Both wheels will then turn together, reducing slippage. Differential lock is maintained only while the pedal is depressed.

That's the extent of the instructions, but there is a follow up Important note and is the only reference of what NOT to do. Again verbatim:

To prevent damage to power train, do not engage differential lock when one wheel is spinning and the other is completely stopped.

So, from what I've read from the various posters here, I think we've all been engaging it and using it appropriately. My "no-no" from earlier turns out not to be a problem, but looks like exactly the correct use.

Hello all,

I've been following this thread and think I've read all the messages. I just bought a BX25 a few months ago. It lives in the garage with a Ford 8N which I've been using for over 30 years. I bought the Kubota because I am getting too "mature" to wrestle with a walk behind blower to clear a kilometer of driveway every time it snows (which it does a lot here in western Newfoundland). The idea of a differential lock seems great but from what I am reading in this thread, misuse of it can be very expensive. I was certainly not warned about how this pedal should be used when I bought the tractor (from Kubota dealer), nor was proper usage or any warnings given in the operator's manual. My question is: can anybody explain under what conditions can the lock be used and how should it be activated? I'm thinking to engage you should be stopped or close to it, rear tires should not be spinning, you should gently put pressure on the pedal until you feel the pin insert/seat itself, locking the differential. Once done, you need to be moving in a straight line. If you need to turn, you should take your foot off the pedal, uncoupling the pin and unlocking the differential. Appreciate it if anyone could confirm or correct my impression.

Best wishes for the new year

Hello snort. I did find the section in the operators manual as mentioned above. From my reading, I think you have it captured pretty much above. I'm thinking that we may not have to be quite so paranoid about using it in the appropriate manner, and poor Carl may have had a very unlucky experience with perhaps a defective lock pin or something...

 

[Grandad4]

I was certainly not warned about how this pedal should be used when I bought the tractor (from Kubota dealer), nor was proper usage or any warnings given in the operator's manual. My question is: can anybody explain under what conditions can the lock be used and how should it be activated? I'm thinking to engage you should be stopped or close to it, rear tires should not be spinning, you should gently put pressure on the pedal until you feel the pin insert/seat itself, locking the differential. Once done, you need to be moving in a straight line. If you need to turn, you should take your foot off the pedal, uncoupling the pin and unlocking the differential. Appreciate it if anyone could confirm or correct my impression.

The diff lock on the BX is pretty much the same as any other tractor... you push a lever to insert a "cog", or pin of some kind between the two opposite sides of the rear differential to join them so they turn together. Obviously, if you do that while one wheel is spinning and the other is stationary, the pin and the gears are going to take a beating. Abuse it often or hard enough and something will break. Kind of reminds me of a high school buddy I knew long ago who was always showing off how he could speed shift his 3 on the tree '59 Ford. He couldn't figure out why he needed to replace the transmission so often!

Take it easy, and it will last forever. I think if you check the owners manual carefully, there should be a section that describes how to operate the diff lock.

 

[radioman]

snort- I think the fears of diff lock breaking on the BX's is overblown here. I use mine every time I "feel" I need it. So use it with caution anytime you want to.

Sometimes when mowing in a ditch and its a bit wet and I want to start to move out and 4 wheel is not engaged, I just simply step on diff and slowly move till it starts to lock rears and its 99% effective getting me out without ripping the lawn or making skid marks. When plowing the snow in 4wd, IF I am in deep heavy snow on grass/dirt and I start drifting or spinning, I just engage my diff lock to get that extra ommph to push. When I was in mud pulling a trailer, all 4's were slipping, and I see my rears is slipping more then other- I engage the diff. :thumbsup:

EVERYTIME- I get myself out of that bad spot- I just thank for the diff lock! I always release it as soon I get out of the bad spot. There is NO need to leave engaged.

It might be me but I still don't understand the fears of diff locks breaking or how it was designed.

 

[Kubota-guy1911]

Hey guys and gals,

In my BX2350 parts exploded view book, looking on page 64 of the differential parts break down, it looks to me like the locking pin is #130. When actuated by the shift fork from the pedal, the pin will fall into the holes in #70 and #120 when they LINE UP, locking them together. Obviously these holes aren't going to be lined up all the time.

I've used my differential lock (on soft ground or icy/snowy condtions) dozens of times and here's how I do it. When stopped, VERY SLOWLY, spin the slipping wheel with LIGHT pressure on the locking pedal. You will feel the locking pin slip right in smoothly and the pedal will go al the way down. You can't force hardened steel parts to move when there is no place for them to go without breaking something.

kj

 

[Doppelgangar]

Good to see some ome looked at the Owners manual and has seen why a lot of you are not reading the owners manual.

The manual does not say to have the tractor stopped or engage the lock when having one wheel spinning. It is clear that you need to put your manual on the internet as then you will have a chance to do some reading.

Dif lock should be engaged when there is slip in one wheel and not the other eg. On the move.
At the time of engagement reduction in power should be undertaken. this will also stop the slipping of the faster wheel.

Power can be restored once the the lock is fully engaged. If tractor is stopped the clutch should be depresed while the engaged processed is undertaken.

Do not jump on the pedel as this will damage other parts.

When pushing snow or going up or down steep grades the diff lock should be in to aid traction. It is not a device to get you unstuck once the tractor has stopped moving. that is what a tow vehicle is used for.

As in one post the author has used the diff lock to stop him leaving skid marks on the lawn.

 

[wcampbell47]

I was at my dealer for some reason and became engaged in a conversation with one of the mechanics - actually the one I prefer to work on my machine. He was repairing an RTV for this very reason. Apparently the drivers continuously stomped on the diff lock while the tires were spinning eventually shearing the pin where it fell through to the bottom and punched a hole in the case.

Problem mostly caused by operator error.

I have been careful with my b7510 and prefer to engage 4WD rather than stomp on the diff lock. Use the diff lock as a last resort.