How to Use your Kubota’s Differential Lock

Credit goes to Bill from www.dieseltraders.com.au who helped us clarify some of the technical details in this article.

The Role of the Differential
This is a quick article that discusses how to engage your Kubota’s differential lock and why you might want to do so. But first, we must understand what the role of your Kubota’s differential is, and why we can get into a situation were we lack adequate traction.

When you turn the steering wheel to make a turn, the inside tires travel a shorter distance than those on the outside – they are traveling at different speeds. The differential equipped on your Kubota allows your tractor to turn because it lets the rear tires rotate at different speeds. Without it, handling your Kubota would be very difficult and wear or damage to the tires and drive train would likely occur.

Your Kubota is equipped with a non-limited slip or open center differential – that is, your differential will favor the wheel that is easiest to turn. This allows us to steer around, but, it also means is that if one wheel starts to loose traction or comes off the ground completely, the differential will send most of the engine’s power to that free wheel. Traction is lost.

What does Locking the Differential Do?
Most Kubota tractor’s have the ability to lock the rear differential. This simply locks both rear wheels together and drives both of them simultaneously without the possibility of one side free wheeling. The differential is no longer favoring the wheel easiest to turn – it is sending power to both. Note – the engine’s power is not increased, but, the power it is generating is better used because your Kubota has a better grip and is not freely spinning.

How to Engage the Differential Lock
You engage the lock by stepping down with your right heel onto the differential lock pedal. If the tractor is not running and the gears in the differential are not turning, the pedal will not depress fully. During normal operation that pedal will depress fully and engage the lock providing that boost in traction.

When to Use the Differential Lock
Because the differential system on your Kubota allows the rear tires to turn at different speeds, locking the differential should only be used when traveling in a straight line. If you lock the differential and then attempt to turn, you put extra strain on the differential lock, possibly leading to its or another component’s failure.

You should lock your differential whenever additional traction is required – like in slippery or snowy conditions or when you are bogged down in the mud. Although additional traction that the differential lock provides is handy, it is a good idea to use the lock only when necessary and for short periods. The planetary gears in the differential generate more heat and when the lock is engaged, so do not just drive around with the differential locked during normal work.

Service Department Vic

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8 Comments »

  1. Jason Said,

    May 6, 2009 @ 10:17 am

    How do I get my Kubota L185 out of differential lock if it will not disengage

  2. Vic Said,

    May 6, 2009 @ 8:07 pm

    Jason, have you been trying to pull up on the pedal? Try to see if the linkage is siezed where it enters the tractor body. Sometimes you can get it to pop up if you drive in reverse for a few feet. Listen for any heavy clicking noises and try oulling up on the pedal at the same time. Once free, investigate why it’s sticking.

  3. Ben Said,

    November 8, 2009 @ 12:39 pm

    I have a Kubota M9540. Do I really need to make sure both rear tires are turning before engaging the differential lock to prevent damage to the drive system like it says in the manual? If so when someone is stuck and both rear tires are not already turning damage can be done to the drive system when the differential lock is engaged? I am confused this does not make much sense?
    Thanks

  4. Vic Said,

    November 9, 2009 @ 9:35 am

    Kubota wants you to engage the diff lock before you get stuck or require that extra push because when you engage it with one axle motionless and the other under torque and turning, you put a substantial amount of stress on the diff lock engagement tab that locks up the motionless axle.

    When stuck, engage the diff lock with care. “Idle” the engine and driveline until you feel the diff lock up, and only then, power up the driveline to free your tractor up.

  5. Giles Allan Said,

    November 19, 2009 @ 4:11 pm

    I have an L2000DT. This tractor is classified as 4WD and has a lever on the rear left side to engage the rear with the front wheels when desiring 4WD. Apparently it also has this differential lock on the right side. I guess then, to really be in 4WD mode, I need to have both rear levers depressed???? If I have none depressed, does that mean I only have front wheel drive – don’t think so???? A bit confused as you can see. Can anyone clarify for me, thanks.

  6. scott Said,

    January 14, 2010 @ 4:46 pm

    Hey Vic,
    I have an old 1500 kubota. I only have a foot pedal for increasing the engine speed. Is there a top mount lever for fuel feed? My dash area has a grommett but nothing was inserted when I bought the tractor. If you have a picture of a complete dash that is original, that may help me in restoring this little gem back to original. My tractor is a L-1500 gray market serial # 44782. Any help will be greatly appreciated!

  7. Jay Said,

    January 31, 2010 @ 8:21 am

    I have a L1500 dt and have been trying to find the drive shaft that goes between the transfer case and the front axle. I have been on this search for 6 years, is there any where i can get one new or used. Any help will be greatly appreciated!

  8. Mauisurfer Said,

    August 6, 2010 @ 11:07 pm

    Kubota B8200HST with 4WD, good tractor, love it, had it for 20 years, but the differential lock has NEVER worked. Lever seems move down, but how can I tell if it goes down far enough? It does not seem to engage anything when it moves.
    Suggestions appreciated, thanks

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