B21 Broken Differential

xcdhracer15

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l2850
Jul 14, 2014
12
0
0
maine
bought a B21 yesterday with ~1300 hours on it with a broken differential.

The official wording from dealership was:

"Removed the backhoe attachment, removed the seat assembly, removed the fenders to gain access to the transmission top cover. Removed the top cover and found ring gear bolts are sheared off, the ring and pinion gear set, carrier, rear axle case, and some transmission gears damaged. Estimated cost of repairs $6500."


Will any of the other B series rear cases/ differentials bolt right on? I'm capable of doing the work just don't really have ~20+ hours to tie up in it right now. I paid $1500 for it so I'm fine with putting some money into it.


What have people ended up spending to fix this type of issue and how many hours did it take you?
 

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100 td

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B21TLB (B21, TL421 & BT751) Toyota SDK4 T116 Bobcat
Aug 29, 2015
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Last edited:

mikester

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M59 TLB
Oct 21, 2017
3,125
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Canada
www.divergentstuff.ca
bought a B21 yesterday with ~1300 hours on it with a broken differential.

The official wording from dealership was:

"Removed the backhoe attachment, removed the seat assembly, removed the fenders to gain access to the transmission top cover. Removed the top cover and found ring gear bolts are sheared off, the ring and pinion gear set, carrier, rear axle case, and some transmission gears damaged. Estimated cost of repairs $6500."


Will any of the other B series rear cases/ differentials bolt right on? I'm capable of doing the work just don't really have ~20+ hours to tie up in it right now. I paid $1500 for it so I'm fine with putting some money into it.


What have people ended up spending to fix this type of issue and how many hours did it take you?
Did some renter drive it off the back of a moving truck? That's some serious damage to a lot of components.

Like the previous owner I probably would have sold the machine to a wrecker or parted it out myself. You'd probably get decent coin for the backhoe and sub frame and possibly the engine if it isn't buggered too. Good luck on the 20 hours for all that listed damage.
 

North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,300
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Sandpoint, ID
The dealer is way off on parts, my quick check says less then $2k in parts for everything new.
But then again they throw a pretty penny at it in labor cost too.

I did one a couple years back, pretty simple, took 2 easy days from start to finish.

I have the WSM (aka service manual) for it if you need it.
You can go to Kubota directly to get part #'s:
https://apps.kubotausa.com/illustrated-parts/
 
Last edited:

lugbolt

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ZG127S-54
Oct 15, 2015
4,807
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Mid, South, USA
I have done a couple of them, and B20 both. Definitely not an "easy" job by any means but it's not that bad either. Worst part is just getting down to it. Lot of stuff in the way. $6500 worth? Hard to say without it being in front of me. If case damaged and other gears, quite possible to be that expensive. Also remember that labor rates are getting close to-if not over-$100/hr nowadays. So 14 hours labor could potentially be $1400+.
 

Mark15

New member

Equipment
Kubota B20
Feb 17, 2017
50
0
0
Ohio
Anybody ever seen issues with the front differential? My B20 seemed like it was rolling a little rough, kind of notchy feeling the last time I had it out. Kind of felt like gears not meshing quite right. Didn't like that feeling at all!

Seemed like it might be the front end, but happened whether in 4wd or not, of course I think the front axle internals still rotate when moving even when disengaged since the hubs do not unlock like on a truck.

Front differential seemed a little warmer than the side gearboxes, but it may have been heat from the chassis /frame since it is all bolted together. Guessing I need to get all 4 wheels off the ground and start turning things to try to isolate it. :(
 

Mark15

New member

Equipment
Kubota B20
Feb 17, 2017
50
0
0
Ohio
Thanks Lil Foot. That was what I was afraid of. Hopefully I can isolate it before too many other parts are damaged as well.