# L3250 diff set-up



## moray (Jun 29, 2009)

I (foolishly!) agreed to replace the main differential casting, after it cracked where the top link brackets bolt on, for my neighbour.

However, I'm stuggling to find the specifications for how to shim the diff sideways (ie. the main diff carrier bearings) in the new casting.
As helpful as the dealer has been at supplying the relevant parts of the manual for setting up the differential and sandwich section, they claim there's no other parts of the manual.
The only mention about the shims, is to use the same number of shims when rebuilding the diff into the casting.

The only other mention in the pages of the manual I've got that could concern the shims, is under the Spiral Bevel Gear Turning Torque, where it mentions that if the torque is not within spec, recheck the differential gear turning force, backlash and tooth contact.

I've got all the details for checking backlask/tooth contact, but I've got nothing (and the dealer says there's nothing) about the differential turning force?

Can anybody help provide me with the relevant info?

At the current moment, I'm considering rebuilding the diff back into the old casting, and measuring turning force, and any play/clearance.


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## Leon (Jun 23, 2009)

I recently did work on an L2950 and found the Kubota service manuals to be lacking in information and peculiar in the way they set up disassembling procedures.

My general rule of thumb for differential bearing preload(turning force) is that it should be able to be rotated with one hand, with slight drag to no drag and should not freewheel like the Wheel of Fortune, nor should it take 2 hands to rotate. This will give you between 0-8 pounds of preload.

Whenever I have a transmission/rear end completely apart, I follow this procedure for reassembly of the pinion and differential assembly:

1) Set the bearing preload on the differential. Remove differential and set aside.

2) Install pinion(spiral bevel gear) using same amount of shims as original set up.

3) Reinstall differential and move shims around to get proper gear backlash.

4) Check tooth contact and add/remove shims from pinion if not correct.

5) Recheck gear backlash one last time and your done.

-Leon


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## moray (Jun 29, 2009)

Thanks for that.

I was kind of heading that way, and just building it up and measuring the pinion turning torque.

I built the diff up using your method, and it feels about right, but I'll get a small torque wrench from work tomorrow, and double check the turning torque.

I seem to of had a bit luck with the shims, as all I needed to do was swap one from side to side on the main diff bearings, to get the right amount of backlash, and the correct tooth contact.


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