CK2610 Difficulty changing from 2 to 4 wheel drive (and back)

[pmhowe]

Most of my work is off-road, so I normally leave the tractor in four wheel drive. However, recently I have had to travel a half mile or so to another location, over paved roads. I have discovered that it is extremely difficult to change to two wheel drive. Is there an adjustment to the linkage I need to make? Thanks in advance for the help.
PMH

 

[repete]

I found there were a number of things that can affect this. I will make the assumption it is a gear connection and not a clutch system to engage.

1) Front tires low of air pressure or little to no tread left. Basically they are rotating at a different speed than the rear causing a "bind" in the drivetrain. Perhaps vice versa front to rear but usually it is the front that wear out.

2) Wrong size tires. Tires larger or smaller than stock will change rotational speeds causing a bind as above. Just a BTW, I have two tires on the rear of my 2550 that are stamped the same size tire by two different manufacturers. One tire is 3" taller that the other. I wish I could find a true "standard" for tire sizes. Maybe there is no standard...

 

[IndyJay]

I have a similar experience with my DK4510 Manual Shuttle. I had read that Kioti tractors have a little more aggressive front wheel assist than other tractors. I use my tractor almost exclusively off-road but having learned that, I am a little more selective in using the 4WD. Unlike my previous tractor, I take it out of 4WD even when crossing the road or driving around in my barn lot.

It has become habit to disengage 4WD while still on turf while approaching the gate to the road. I apply steady, firm pressure on the lever while still rolling with the clutch in and that seems to make a difference. Having only 68 hours on it, I am still getting used to the little differences from my previous tractor of 27 years.

 

[Doughknob]

Chuckling OP. There are other threads here where we debate the need or benefit of leaving a tractor in 4wd all the time. For me, I leave mine in 2wd unless absolutely need 4wd for a specific task. And my Bobact is sometimes hard to get in 4wd -- not "real" hard, just tricky; I have to massage the forward/reverse pedals to get it to pop into 4wd.

I attribute that to lack of synchronizer gears in engagement system so it is just normal. Going back to 2wd has never been an issue, though. Have you checked all accessible linkage for freedom from rust, mud, debris?

 

[CobyRupert]

It’s a common and normal thing to have the drivetrain bind. Either the front tires or rear tires will try to push or pull the other axle more than that axle is turning. (It’s why a tractor in 4wd will often leave rubber marks on pavement) It’s a function of the 4wd gearing between the axles and tire sizes. Ratios will rarely ever be perfectly matched. Most tractors are designed so that the fronts are always pulling a bit more than the rears are turning.

Various techniques to unbind include:

-Stop and try lever when beginning to back up and unloading drivetrain stress (try to unlock when drivetrain is in the “slack” between going forward and reverse). This may take a few attempts rocking forwards and back.
-Raise front front tires with FEL to relieve stress. Slightly rocking may also help if required.
My preferred method:
- Moving slowly, and applying a little pressure to the 4WD lever, I burp the throttle (or hydro pedal if applicable) so tractor lurches. In that moment when tractor is between accelerating and de-accelerating (“slack”) and there’s no stress in the drivetrain the lever moves like a knife through hot butter.

 

[Buggs67]

I usually drive straight ahead in 4wd figuring it removes any stress/binding, then pull up on lever and apply a little forward thrust.

The idea of lifting the front wheels with the FEL sounds good too.

 

[repete]

I agree with what you are saying about the design in the rotational speed. The point I was making is when your front tires lose an additional inch of radius, it REALLY changes that ratio difference. When they are under inflated (less radius) it changes the ratio as well. Couple worn tires with underinflation and you have double the change in radius.
I have bought many sets of fronts for my Kubota over its 6100+ hours of use and with each new set I am really happy with the resulting shifting ease. Matter of fact, it is due for another set now.

 

[CobyRupert]

Yes, I believe every 1” change in tire radius is ‘about’ a 6.28318530 inch change in tire circumference. (That’s 1” x 2 x Pi)

(I think this is also true for a under-inflated tire, even though the radius only changes at one spot of the tire; i.e. “it’s only flat on the bottom”)

 

[Buggs67]

Speaking of front tire inflation, what are most of you running? I'm getting ready to install my front chains for winter traction and usually deflate to install the chains and then inflate at higher than normal running pressure to tighten the chains and increse traction.

 

[repete]

I usually inflate to the max pressure on the tire.
And you and I have the same kind of flat tires Coby! Only flat on the bottom.