Traction Hard to use diff lock

[Lowrider2120]

Just bought (19 hrs) a CK3510 HST SE with cab. Had 40 CY of fill delivered to my shop build site today and I'm having a devil of a time making the rear diff lock engage. The lever is not very long anyway but when I can get boot heel on it, it's a bear to depress and seldom engages the lock. Am I getting weak in my old age or are the new tractors really stiff and hard to use?

 

[Looking4new]

Have you tried rocking the tractor back and front a little bit while stomping on the lever?
My ck27 hst was hard to get to lock at first.

 

[redman135]

Hello Lowrider2120, 2 things, 1st, put wd40 or some other penetrating oil on the shift where it goes into the trans. It may not have enough grease from the factory.
2nd, when you want engage diff lock turn left or turn right to make the teeth line up for the diff lock to engage. Driving in a straight line will not let the teeth mesh, so the diff lock won't engage.

 

[square1]

Why are you trying to forcibly engage it? Seems it would engage easily in a situation where it is needed, not so much if conditions don't merit it?

 

[oosik]

Square1, that was my thought also. I one rear wheel is slipping - the diff lock should engage easily. No slippage, no need for the diff lock, engagement won't be so very easy. Just don't attempt to engage the diff lock when one rear wheel is spinning wildly.

 

[fuelhog2000]

Mine was the same way but has gotten easier to engage now that I'm at 50 hours. Like others said it will engage easier with wheel slip.

 

[ovrszd]

Not familiar with your specific tractor.

Generally the pedal activates a spring loaded mechanism to engage the diff lock. Holding the pedal down doesn't mean it's engaged. When one wheel slips the tensioned mechanism will engage. Same principle applies when you remove your foot from the pedal. Mechanism will disengage when tension is removed. Most pedals are difficult to depress. The pedal spring is generally strong. This is to prevent you from accidentally engaging the mechanism. It should be somewhat difficult to engage.

 

[Lowrider2120]

Tried everything except the WD 40 spray which I'll do this morning. Tried stopping the engine too...no joy. With the engine off I can barely push the lever down with my hand. I'll soak the shaft some and see if that improves things. Good to hear it improves with age like a good sippin whiskey!

Thanks folks for the replies!!

 

[ovrszd]

I've not tried it, but I believe I would have difficulty pushing the diff lock lever down by hand on my Kubota. When using it I have to put considerable downward pressure on the lever with my heel. To the point of lifting myself slightly in the seat.

 

[Lowrider2120]

Guess I'm spoiled by the Fords I've owned in the past...always easy. My little BX has a lever forward on the floor and works as it should...easy to use and instant "two wheels driving".

My thought is the spring is too strong on the CK but I'll give it a chance to loosen up some before going that route...if I can get it to work.

 

[ovrszd]

My Ford's pedal works easily too. It's located rearward on the floorboard so you gotta "fish" around with your heel to find it, but depresses easily.

I guess you could explore changing the pedal spring to something softer??

 

[atsah]

My Massey is the same, pain in the neck to engage it, I have no use of my legs so I installed a 16 inch handle that comes off of it to give me leverage to push it with my hand but it's still a pain, I wonder if I can replace the spring to something manageable.

 

[Oldpath05]

My Ford's pedal works easily too. It's located rearward on the floorboard so you gotta "fish" around with your heel to find it, but depresses easily.

I guess you could explore changing the pedal spring to something softer??

Must be nice to have an easy operating diff lock lever, hope you don't rub it in, but here in the real world.......

Is having an easy to operate diff lock to much to ask for when buying a new tractor. Mine has been hard to hold down since day one, that's why I made a hold down knob to keep it in fully locked in till not needed, to me there's nothing worse than something not fully engage.

Seams to me that tractor manufacturers could do a lot better job in this diff lock area so to make it easier to lock in, something like a 4x4 pickup, move a lever and whala, it's 4 wheel drive, these foot levers on tractors are terrible especially with foot pain like plantar fasciitis, you wouldn't think feet could hurt so much for so long.

 

[square1]

My Ford is smooth as butter. When i think diff lock might be needed i just rest my heel on the pedal. When it is needed i feel the pedal go down under tbe weight of my foot. I remove my foot and it stays down until it decides to unlock They should all work so easy

 

[ovrszd]

My Ford is smooth as butter. When i think diff lock might be needed i just rest my heel on the pedal. When it is needed i feel the pedal go down under tbe weight of my foot. I remove my foot and it stays down until it decides to unlock They should all work so easy

Yep, that's how my Ford works as well.

 

[ovrszd]

Here's my unsubstantiated reasoning for why most are hard to engage:

1. The manufacturer doesn't want you to use the diff lock anymore than absolutely necessary.

2. The manufacturer doesn't want the diff lock to remain locked with no input from the operator.

Both of these assumptions are because the rear diff can be easily damaged when locked. So they want it uncomfortable to engage and easily disengaged. Will save some repairs later. I don't think this is much of an issue on older tractors because of the heavy duty design of the rear differential and it's components.

Take this information with consideration.

 

[Oldoak]

My Ford is smooth as butter. When i think diff lock might be needed i just rest my heel on the pedal. When it is needed i feel the pedal go down under tbe weight of my foot. I remove my foot and it stays down until it decides to unlock They should all work so easy

It takes just a slight pressure with my heal to engage the differential lock on my Kubota L4200. Otherwise the operation is identical.

I also try to maintain a strait coarse and avoid trying to turn left or right while the rear differential lock is engaged. It puts less strain on the drive components.

I think there is a big difference between the much larger tractors which full time farmers and ranchers use compared to weekend and hobby farmer CUTs.

 

[mj007]

..................seldom engages the lock. .............

Kinda like finding the lock detent on a steering wheel, you gotta keep it pushed down until the drivetrain catches up and it locks(if you take your foot off the pedal it will unlock).

 

[Lowrider2120]

Paint....maybe paint that's making the diff lever hard to move with some contribution from the overly heavy spring. I drown the shaft with WD where it enters the case and it didn't help. I needed the diff lock maybe 10 time today and I didn't even try to engage it...just hit the backards pedal and didn't need it any more.

Given how slippery things are when you need the lock I don't think it hurt a thing if it was engaged frequently and for a long period. If it does, I bought a wimpy tractor...like my little tractor so far if I could just use all the options and standard equipment.

By the way, the "one size fits all" backhoe sub frame won't fit my WoodMaxx 8600 hoe...that I can fix but I shouldn't need to do so.

 

[CalG]

If you take a moment with the parts manual to see how the mechanism works, it will pay dividends in understanding and your expectations.

With a simple "pin in a hole" system. It makes sense that a steady but gentle pressure on the pedal will engage the diff lock when the hole comes around. Continued pedal displacement will continue the diff lock action. If the diff lock is under stress, a single stab at the pedal will keep the diff lock engaged, friction and load supplying the retention force, until the need is passed.

Play with it in comfortable conditions. The better you know the system, the better you will be able to utilize the feature.

ps
The Hurlimann 435 has locking diffs both front and rear. The front lock is Hydraulic actuated. Let me say that in 4WD, with locked diffs all around, this little tractor will claw it's way up most anything, ;-)