Rear Differential Lock Question

[Henro]

I know it has been stated a million times NOT to engage the differential lock when the rear wheels are moving.

Why is this?

Seems to me that something needs to be engaged for the differential lock to become active. Like a pin going into a disk with a bunch of holes in it. A hole must be aligned with the pin, or the pin will not go into a hole.

I know I am missing something and cannot visualize what the exact mechanical system is. Does something need to be aligned in order for the differential lock to engage?

Is the message really "Keep trying until you get lucky, and things eventually end up in alignment when the wheels are not turning?" With a do otherwise and suffer the consequences caveat?

Help me understand...

 

[xrocketengineer]

You are right. You need some motion to align the pins with the holes so that they go in. However, what you want is that the relative motion between the two to be a minimum in order to reduce any shock loads that will cause damage. You don't want to have a tire spinning at full speed and try to engage the lock.

 

[Pawnee]

When I think I might need it I step on it beforehand and if a wheel slips it goes in.
I've done that on 3 Fords for 30 years and now the Kubota.
I didn't know it was wrong.
I've never heard a clunk when it locked, I find out at the top of the hill if it locked or not.

Of course I wouldn't step on the lock if one wheel was spinning in the air while the other was stuck.

 

[ItBmine]

You can engage while moving, just not spinning....in other words, loss of traction and wheels are spinning faster than travel speed.

 

[NCL4701]

This may be totally wrong and part of the reason I’m posting it is in case it is, I’d rather be subject to correction than subject to astronomical repair bills.

If I have one rear wheel spinning, one not spinning, and tractor going nowhere: HST pedal to neutral to stop everything, engage diff lock, slowly go forward/backward until either tractor starts moving or previously stationary wheel starts spinning in time with previously free spinning wheel. Once it has been visually confirmed both wheels are spinning in concert, continue with diff lock and then (if tractor still not moving) it’s full send forward, backward to dig out. When out, release diff lock and if lock pedal doesn’t pop up, slowly back/forward a little until it does pop up.

My thought has been to avoid a shock load upon engagement but, once engaged, get on it to the degree necessary.

If that’s improper, abuse, asking for problems; instruction and explanation of the basis for proper procedure would be appreciated.

 

[RCW]

NCL4701 - that's how I've been engaging the diffy for 20+ years.

Stop, depress lock pedal, then slowly move F or R to allow it to engage....can feel pedal depress a little more when it locks in.

Had a 2WD JD425 garden tractor. Used it a lot..

 

[Henro]

I am a bit concerned about the differential lock on my BX2200.

It does not seem to want to engage, and I have read horror stories where posters have said that they somehow broke the diff lock and a piece fell down and got jammed between something and the transmission case, and the case cracked. Big dollar repair.

I got the BX in a position where a front wheel and rear wheel were each losing traction, and I could not get the tractor out, since my diff lock would not engage. I was not is a very bad position at all as far as tractor position goes. But I had to use my B2910 to pulls the BX back a bit so the wheels would grab and that was the end of it. No doubt in my mind that the diff lock if it had engaged would have given the BX the ability to back out on its own.

Same thing happened with a jeep CJ7 years ago leaving a guy's driveway that was flat, but there was a small drainage ditch at the road that I did not see, and one front and one rear was spinning. Solution at that time was the friend stood on the rear bumper of the side that was spinning and that gave me enough traction to back out...

Edit: I have always followed the procedure that RCW outlined above...

 

[xrocketengineer]

I am a bit concerned about the differential lock on my BX2200.

It does not seem to want to engage, and I have read horror stories where posters have said that they somehow broke the diff lock and a piece fell down and got jammed between something and the transmission case, and the case cracked. Big dollar repair.

I got the BX in a position where a front wheel and rear wheel were each losing traction, and I could not get the tractor out, since my diff lock would not engage. I was not is a very bad position at all as far as tractor position goes. But I had to use my B2910 to pulls the BX back a bit so the wheels would grab and that was the end of it. No doubt in my mind that the diff lock if it had engaged would have given the BX the ability to back out on its own.

Same thing happened with a jeep CJ7 years ago leaving a guy's driveway that was flat, but there was a small drainage ditch at the road that I did not see, and one front and one rear was spinning. Solution at that time was the friend stood on the rear bumper of the side that was spinning and that gave me enough traction to back out...

Edit: I have always followed the procedure that RCW outlined above...

I have a few small spots that I mow on two wheels (I should use the trimmer) with my BX1880 that I have to engage low range and some times the diff lock. Like RCW says, the pedal goes down partially and as I slowly try to move it fully engages, the pedal goes all the way down and I start moving.

 

[old and tired]

...I got the BX in a position where a front wheel and rear wheel were each losing traction, and I could not get the tractor out...

Does the BX have split brakes? And could you have hit the brake on the tire that was spinning to get out? (seriously, I don't know the answer...)

 

[6869704x4]

Does the BX have split brakes? And could you have hit the brake on the tire that was spinning to get out? (seriously, I don't know the answer...)

I guess it depends on how the tractor is setup. For me it's easier to lock the rear rather than bring my left foot over to the brakes. I still need my right foot for the go pedal.

 

[Henro]

Does the BX have split brakes? And could you have hit the brake on the tire that was spinning to get out? (seriously, I don't know the answer...)

No split brakes on a BX. Wish there were...

 

[steveh]

On my 4701, as with my L3000 before, tractor must move slightly almost every time to engage rear lock. I am in an often snowy/icy region and use the rear dif' lock frequently.

All my tractors have been manual transmission.