2520 Differential Lock doesn't play well with the other levers

   #1  

C-Range

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Maybe it's just that the new tractor only has 3 hours on the clock, but I'm having a heck of a time getting the differential lock to "kick" in. On my 2305, I could pop the diff lock in without a moment's thought. On this new machine, it doesn't want to go much of the time. I step on the lever and it tries to spring back up against my foot. Eventually, it will drop to the floor and take hold (long after the tire has made a nice bird bath in the ground).

Is this an indication of something out of whack, not broken in yet, or normal to this machine?

On a side note, I'm planning to weld a small tab onto the lever. With it backed into the little pocket in the fender area, I miss it half of the time with my boot heel.
 
   #2  

pdp11

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John Deere 2520 CT
Mine is also a bit fussy about engaging. I just keep light pressure on it with my heel until it engages. I have a vision of whatever it is that forms the actual lock having to rotate about half a wheel turn until it finds the spot where it engages.
 
   #3  

wooden

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Mine is also a bit fussy about engaging. I just keep light pressure on it with my heel until it engages. I have a vision of whatever it is that forms the actual lock having to rotate about half a wheel turn until it finds the spot where it engages.

I wouldn't call mine difficult but I do the same thing, a little light pressure on the heel and it pops in while I am moving forward. Maybe you just need to use it a few more times to find the groove.

Wooden
 
   #4  

dmay

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Winnipeg, MB
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2010 JD2320
On my 2320 I find I have to hold the lock lever depressed all the time when I need it on. The manual states:

NOTE: Rear wheel slippage will keep differential lock engaged. Lock will automatically disengage when traction equalizes.

I'm sure the tractor feels traction equalizes a lot sooner then I do. I also find the lever way too small for a heavy winter boot to easily find.
 
   #5  

Tractor Pilot

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Colorado
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1997 John Deere 770
Ensoll,

On my JD770, it could take a few moments of holding the pedal before the differential lock engages. The jaws on both the right and left axle shafts have to align before the shafts lock together. Depending on the difference in the rate that each axle shaft is turning will determine how quickly the differential will lock. If both wheels are spinning at the same rate and the jaws are not aligned, the differential will never engage. The mechanics of your tractor may vary.

Bruce

P.S. My Operator's Manual says not to engage the differential lock when one wheel is spinning and the other is "completely" stopped.
 
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   #6  

beenthere

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My understanding is the diff lock should not be engaged when the wheels are moving. It is like a mechanical connection that must lock, and there is a risk of damage trying to engage the pins during movement.
I stop any wheel motion for the diff lock.
However, engaging the 4 wheel assist I will do on the move with no problem.

I very rarely have a need for diff lock, but use the individual brakes to stop or slow a single wheel spinning due to loss of traction.

You may have a different take on that. ;)
 
   #7  

ipwanab

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Southern Indiana
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Kubota L2501
I engage mine a LOT when I cut grass, due to having spring spots in the yard. I have discovered if locked in the tractor does very little damage to the wet yard, but if I forget and one wheel starts to spin its all over before I notice.If any one has a definitive answer on engaging stopped vs rolling please respond, I have not been stopping but would if I thought it would hurt the machine. Mine will engage easily but only when its ready.
 
   #8  

beenthere

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I suspect engaging on the move if both wheels are the same speed would have no ill effects. It is when the differential is allowing one wheel to spin and the other stopped that damage can occur. After that, the differential lock just doesn't function any more.

jpwanab
Seems you have the system down good. As long as "straight ahead" is the plan. ;)
 
   #9  

kennyd

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John Deere 3720 CAB/TLB, JD455
I apply very light pressure to my diff lock while moving slow so the pedal drops in gently. You can't really "engage" it fully while not moving because the chance of the pins on the diff lock (#24) lining up to the holes in the hub (#23) is slim to none...

2520 pictured, others similar.
 

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C-Range

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Thanks everyone, your responses are all appreciated. Kenny, I looked at that graphic, though I'm not sure I quite follow how the system is actually functioning from the lever on down to the diffy. I still wonder what the spongy feel in the lever comes from and the other point of contention is that I've had plenty of time on the 2305 to know when the diff lock is going to be needed ahead of time and am in the habit of getting it engaged well in advance. All I ever had to do on that machine was to drop the lever down and it just worked. I never had resistance of any kind, regardless of whether the wheels were turning at the same speed, different speeds, or stopped.

This 2520 diff lock is just not working the same way and causing me far too much distraction which gives me concern for my safety. I'll put in a call with my dealer when I get a chance, see if that sheds any light and report back anything worthwhile.
 
 
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