Fun with a B21 Differential

[yubby]

Just thought I would share the fun I have been having lately with my B21. Was purchased as a rental unit with about 1200 hours on the dial, served me well for about 250 hours. Then developed a click as you would be driving around, that lasted for about 50 hours until under load (pushing dirt) the differential locked (would not go forwards or backwards).

Just 0.2 hours shy of 1500 hours on the meter.

First two pictures are removing the loader.

--Lucas

 

[yubby]

Here is the loader and backhoe subframe removed (weighs about 300 lbs).

And the rear finals as well.

I was hoping to take off the rear finals and discover one of them had frozen, or it was an issue with the diff lock; no luck!

 

[yubby]

After removing the seat and 3 point assembly I finally started to find where the issue was.

 

[yubby]

Now if this was a common repair I am guessing that the pinion (they call it a spiral bevel shaft) would come easily out of the transmission and this would be a quick fix! Not so easy!

You have to pull the whole transmission assembly, basically splitting the tractor at the center frame.

 

[yubby]

Eventually after separating the HST unit from the Transmission, removing many gears and snap rings you can finally pull out the culprit!

A few calls to Keller Brothers to order parts and another few hours in the garage and I will be back in business!

 

[zenmek]

Looks like you've got your work cut out for ya Lucas! I definitly don't envy you. Good luck. Oh... and welcome to TBN! most people start off a little slower!

Will

 

[Doc_Bob]

Nice job!
Bob

 

[sandman2234]

Setting up the new rear end gears probably isn't as easy as just putting the parts back in the proper place either! To get the correct heel/toe pattern, you have to be good at reading gears, and a whiz at installing the correct shims. GOOD LUCK!!! Take your time and make sure you have everything just right!
David from jax

 

[czechsonofagun]

Looking good - I remember an old mechanic telling me:

everybody can put it back together - b ut to take it apart without braking anything you need to know whatg you are doing.

My B1750 will not unshift from 4wd - means i will be following your footsteps soon enough

Thanks for the pictures.

 

[yubby]

Sandman,

From the looks of things, this isn't the first time this area of the tractor has been apart. I think some of the reason the gears have worn is it was improperly shimmed at some point in the past. (there was 1 shim on the ring side of the differential and 5 shims on the other side).

I am considering taking the assembly (trans/diff) to a shop that specializes in differentials and hoping they take pity on me and can help align everything.

The last thing I want to do is to take this thing apart again, what a pain! I would consider taking it to some of the kubota dealers around Sacramento if they weren't charging extortion rates for parts (30% above kubota list) and labor ($85/hr).

-Lucas