Kubota B3030 HSTC

[taterpicker]

Plowing snow today noticed a clunking noise. forward or reverse. 4 wheel drive only. all three transmission ranges. sounds like a cog missing off a large gear. 10 years old, 500 hours. light use. proper maintenance. no incidents that would have caused damage to drive line.

 

[TripleS]

Sounds like either a front axel universal joint or front drive shaft universal joint

 

[whitetiger]

Sounds like either a front axel universal joint or front drive shaft universal joint

The B series does not have a universal joint in either place.

 

[ptsg]

Sounds like it stripped one of the splined couplers between the transmission and the front axle. Are you on 4WD a lot? Specially on hard surfaces?

Had that happening to me on a B7000. That one used u-joints instead of a straight coupler but it's the same principle.

 

[rScotty]

Sounds like it stripped one of the splined couplers between the transmission and the front axle. Are you on 4WD a lot? Specially on hard surfaces?


View attachment 846594

Had that happening to me on a B7000. That one used u-joints instead of a straight coupler but it's the same principle.

Several here on TPN refer to Kubota's splined FWD coupler as being a part that is designed to wear out so that it protects the rest of the front drive components.... I've no idea if it was designed for that, but apparently that is what it does.

The symptoms match, easy & inexpensive to replace. Look there first. You will have to undo the drive shaft cover. Most of the covers telescope.
rScotty

 

[Paystar]

Several here on TPN refer to Kubota's splined FWD coupler as being a part that is designed to wear out so that it protects the rest of the front drive components.... I've no idea if it was designed for that, but apparently that is what it does.

The symptoms match, easy & inexpensive to replace. Look there first. You will have to undo the drive shaft cover. Most of the covers telescope.
rScotty

I don't know if they are "designed" to wear out, but I had an old Case backhoe that used one of those to drive the hydraulic pump off the front of the engine and I remember changing them every couple years.

Or maybe you mean they are designed to wear before the splines on the shafts do.

 

[rScotty]

I was thinking the same thing. A part like that coupling is going to move and wear, so it would make sense to make it of a material that would wear faster than the splines on the shafts.

So it makes sense that anyone who designed that type of coupling would tend to specify materials to make the coupling wear faster. Maybe not as a truly sacrificial part, but as a side benefit.

Another thought was that if the splines and coupling were intended to wear at the same rate, there would be some way to lube it and keep it lubed.

rScotty

 

[taterpicker]

I doubt it would be a spline problem as both front wheels work as designed. Only hear the clunking noise at about every half rotation of the front wheels

 

[Paystar]

I doubt it would be a spline problem as both front wheels work as designed. Only hear the clunking noise at about every half rotation of the front wheels

Bad bearing? Any seals sweating yet?

 

[rswyan]

I doubt it would be a spline problem as both front wheels work as designed. Only hear the clunking noise at about every half rotation of the front wheels

B2910 here, believe the drivelines are substantially similar.

Blew the rearmost u-joint on the drive line going to the front axle @ around 2400 -2500 hours while dropping it into 4WD pushing the loader into a manure pile.

Managed to destroy the yoke halves as well.

Kubota calls for splitting the tractor to replace it. It can be done without doing that, but it’s a bear.

The driveline is contained in a tunnel that connects the front (bell housing, engine) of the tractor to the rear (hydro, transmission)

Front axle has to be dropped to remove the driveline and a hole (2” ?) has to be punched in that tunnel that connects the front of the tractor to the rear - so the yoke can be (roll) unpinned from and then pinned to the output shaft on the transmission. Can’t get to it otherwise.

Think there’s a write up on here somewhere of a guy that did it, could have been on another site though. Didn’t have much in the way of pics IIRC.

See if you can isolate where the noise is coming from.

If it is that u-joint, let me know and I’ll post some pics of what I did.

Most critical thing to know is where to punch the hole in the tunnel with the hole saw - so you don’t end up cutting the hydraulic hard lines that run through the tunnel.

Good luck.

 

[rScotty]

B2910 here, believe the drivelines are substantially similar.

Blew the rearmost u-joint on the drive line going to the front axle @ around 2400 -2500 hours while dropping it into 4WD pushing the loader into a manure pile.

Managed to destroy the yoke halves as well.

Kubota calls for splitting the tractor to replace it. It can be done without doing that, but it’s a bear.

The driveline is contained in a tunnel that connects the front (bell housing, engine) of the tractor to the rear (hydro, transmission)

Front axle has to be dropped to remove the driveline and a hole (2” ?) has to be punched in that tunnel that connects the front of the tractor to the rear - so the yoke can be (roll) unpinned from and then pinned to the output shaft on the transmission. Can’t get to it otherwise.

Think there’s a write up on here somewhere of a guy that did it, could have been on another site though. Didn’t have much in the way of pics IIRC.

See if you can isolate where the noise is coming from.

If it is that u-joint, let me know and I’ll post some pics of what I did.

Most critical thing to know is where to punch the hole in the tunnel with the hole saw - so you don’t end up cutting the hydraulic hard lines that run through the tunnel.

Good luck.

I remember reading that write up, and thinking it was a clever workaround for a terrible design. But usually front driveshafts are more accessible. Having done yours as you did, would you do the next one the same way? It seems about the same work vs access as splitting a little tractor.

I hope I don't offend anyone, but I do think that concealing the drivesaft like on your B2910 is a shameful design. Though I don't think it is common. Kubotas and most all 4wd tractors have had good front driveshaft access for about the last 50 years. Details vary, but it is typically a sheet metal shield that can be removed to give access to the front driveshaft.
rScotty

 

[rScotty]

I doubt it would be a spline problem as both front wheels work as designed. Only hear the clunking noise at about every half rotation of the front wheels

Well, if it is the spline coupler, you may hear a similar sound whether or not 4wd is engaged. If I'm right...then I believe when you are in 2wd that front drive shaft still turns - although it could make a different sound when the front driveshaft is being driven by the front wheels instead of by the transmission output.
rScotty

 

[rswyan]

Well, if it is the spline coupler, you may hear a similar sound whether or not 4wd is engaged. If I'm right...then I believe when you are in 2wd that front drive shaft still turns - although it could make a different sound when the front driveshaft is being driven by the front wheels instead of by the transmission output.
rScotty

This is correct - the driveline still turns whether or not it is driven from the transmission.

The engagement/disengagement (of the driveline) occurs back in the transmission/transfer case/whatever it is.

 

[rswyan]

I remember reading that write up, and thinking it was a clever workaround for a terrible design. But usually front driveshafts are more accessible. Having done yours as you did, would you do the next one the same way?

Yes I probably would.

I called the dealer to get a price on the splitting the tractor before I attempted it. Service manager ballparked it off the top of his head @ $5K to pop it apart and put it back together IIRC.

I fixed it for a couple hundred.

It seems about the same work vs access as splitting a little tractor.

Yeah, no ... I think splitting it would be a little more involved ... mostly due to having to deal with whatever else (hydraulic hardline, any linkages ) might hiding up in there.

Versus just dealing with removing the front axle - which is relatively easy since it is accessible.

I hope I don't offend anyone, but I do think that concealing the drivesaft like on your B2910 is a shameful design.

No offense taken.

Design is definitely less than ideal, in terms of accessibility.

My (now deceased) neighbor who was a heavy equipment mechanic helped with taking it apart. He owned a (newer) but similarly sized JD ... he couldn't believe the design. Including the fact that the u-joints were not greasable.

OTOH, the components, which are pretty small (IMO) did last for 2400 or so hours. And the tractor had been worked pretty good.

Though I don't think it is common. Kubotas and most all 4wd tractors have had good front driveshaft access for about the last 50 years. Details vary, but it is typically a sheet metal shield that can be removed to give access to the front driveshaft.

Yeah ... a removable cover would have been the way to go.

 

[rScotty]

I won't tell how I learned this, and it only applies when using a holesaw that has a center drill bit that is used as a pilot - and only matters where you may be trying to just cut a hole only a certain depth.

But that pilot drill doesn't need to be more than a little bit proud of the face of the hole saw teeth. And once the hole saw begins to cut, the pilot bit can be moved back to being just flush with the hole saw teeth.
If you let it stick out any more than that, no matter how carefully you monitor the depth of the hole saw - that pilot drill is sticking out enough to be drilling through something else entirely - like the bottom of your sailboat for instance....

rScotty

 

[taterpicker]

Bad bearing? Any seals sweating yet?

nope, not yet

 

[rswyan]

Here's some pics:

​

Last pic shows the location of the hole that has be drilled in the "tunnel" to access the roll pin holding the old yoke on so that it can be removed and replaced.

No guarantees that the locations of the hydraulic hard lines are the same on a B3030 though.

Maybe compare B2910 ---> B3030 exploded parts diagrams up on Kubota's website ? Might give a good idea.

IIRC, the u-joint/yokes are a single assembly: rear yoke/u-joint/front yoke.

 

[whitetiger]

The B series does not have a universal joint in either place.

I guess I misread the model number, I thought this was the later B series design with splined couplers.

 

[rswyan]

I guess I misread the model number, I thought this was the later B series design with splined couplers.

There is a splined coupler on the B2910 - it’s further forward on the front drive shaft which has no u-joints IIRC.

Might be it on the end of the front shaft sticking out of the axle in the 2nd pic above.

Possible that it might allow removal of the rear driveshaft that goes goes to the front driveshaft that goes to front axle without having to remove the front axle itself. I wasn’t able to ascertain whether it did or not. Its location is somewhere up around the middle of the engine.

On the B2910 the task of removing and replacing the rear drive shaft (and u-joints/yokes) is complicated by the loader brackets if you have a loader installed.

IIRC the loader brackets get in the way of removing the carrier bearing and its hanger. Can be done but it’s a PITA.

 

[rswyan]

Drivetrain on the B2910 and B3030 are very similar (despite the difference of the layout of the exploded parts diagram) - with the exception that the carrier bearing appears to be integrated into the bell housing on B3030:

​

Versus the B2910 which utilizes a separate external carrier bearing mounting (Items #120 and #210):

Didn't check, but I'd bet that they share a lot of parts in common.

If the picture is accurate, the fact that the carrier bearing is in the bell housing may be an obstacle to removing the rear driveshaft without splitting the tractor.

Would need to get down there and have a look to really tell how it's put together.

First thing to do would be to see if you can pin down where the noise seems to be coming from.

If you can't tell when with the engine running and it moving, then maybe jack/block it up with all the wheels off the ground (with the engine off) and put it in neutral and give the wheels a spin.