Excessive lash in Front Diff?

Tractor Dr. · Jun 24, 2007

While doing some cleanup work on my property I put the bucket down enough to raise the front wheels of my tractor. When I got off the tractor I gave the one front wheel a spin. I noticed that the wheel turned about an inch (measuring at tread) before the opposite side engaged and turned in the opposite direction. This got my attention so I continued to spin the wheel back and forth while observing the opposite side and there definitely is about an inch of spin before the opposite side spins. Does this sound normal? When I drive the front wheel(s) over a small burm I notice the excessive play when the wheel is on the down side of the burm the wheel will quickly travel that inch of play until it catches. Just seems excessive.

Can any you let me know what you've observed? My tractior is a L3130.

Thanks,
TD

Dargo · Jun 24, 2007

I've never actually worked on a Kubota differential, but I've set up several auto differentials. Heck, I can tell you that the marking compound tasts like crap; long story. Anyway, inadequate carrier bearing preload allows the carrier to move when under load and this can cause the backlash to open up. That in turn can possibly cause what you are talking about. However, on some other heavy equipment, like a backhoe or haul truck, the manufacturer calls for greater tolerances and more backlash. As you likely know, the four essential differential adjustments are pinion depth, pinion bearing preload, backlash and carrier bearing preload. Any could cause noise or slop if not shimmed or installed correctly. But, there again, the differential in the Kubota front axle could be of crush sleeve design and not preload shim design. I don't know.

Either way, unless you are hearing or feeling something that feels wrong when driving the tractor, I wouldn't worry much about it. I guess it wouldn't hurt to call the dealer and ask about the design of the differential (which would be easier than taking it apart). If it's shim design, you can shim it tighter, but that may cause problems if it's intended to have some play.

DieselPower · Jun 24, 2007

Measured at the wheels it doens't sound like a lot to me. By the time you go through the differential gears a very small amount of play ends up being quite a bit at the tire tread.

BTDT · Jun 24, 2007

TractorDr, Welcome to TBN. Nothing in your profile, so I don't know if your tractor is new or not, but if you have a dealer near you, I would go there and perform same test on a new unit. Then you will know if you have a worry or not and could discuss it with one of their mechanics or the service manager. Good luck.