Just how good is 4 wheel drive

[k0ua]

Well, it's a very simple construction, most tractors does have electric engagement of PTO and it's the same principle, so the cost of having a lot more safety and ease of use is quite low.

But maybe it's very little new thinking on those small tractors.

Even my Kioti CUT which has electric engagement of the 4WD with a simple rocker switch on the dash does not engage the 4WD by pushing on the brake pedals, even though there is a microswitch on the brake pedals that lights a light on the dash when the brake pedals are engaged and the parking "pawl" lever is engaged. So 90 percent of the hardware is already there, but it does not have that feature like the big tractors do.

 

[CobyRupert]

Look at it this way. All tractors have one wheel drive. Then when you need more traction, you push down on the lever at your feet the locks the rear differential and now you have 2 wheel drive. A so called 4 wheel drive tractor is actually 2 wheel drive all the time, so when you need more traction, you push down on that lever to lock the rear differential, and now you have 3 wheel drive.

It's a significant improvement. I have both types of tractor and it's night and day better getting around in poor conditions with three tires working over 2. In dry conditions, and where you don't really need the most traction possible, 2 wheel drive works fine. I just learned years ago to never take any chances with the 2 wheel drive tractor after it rains. I make sure everything is rock solid dry first!!!

Well...yes & no.
With 2wd: When one tire is spinning and the other is just sitting there, I guess you could also call that Zero wheel drive, cause you ain't driving...you're stuck!!
The motionless tire applies the same amount of torque to the ground as the spinning one....it's just that the spinning tire doesn't demand very much torque (because it's spinning in loose mud) and this isn't enough torque to make the other stationary wheel "turn" and propel you forward.
If locking differential is not possible, a tap of the steering brake on the spinning side increases the torque required to spin and this ups the torque delivered on the stationary side too...sometimes enough to get that tire to turn (propel) the tractor forward..(or spin and turn that side to muck too!)

On my 4wd tractor they put some stops on the "frame" so that front axle doesn't pivot as much as I expected, or as much as the 2wd version probably does. Not sure why? I soon learned that when going through a ditch at 45 degrees you can get opposite corners off the ground (1 front, 1 back tire) and your "4WD" quickly becomes "ZeroWD".
...until you step on differential lock and use "1WD" (1 rear wheel).

 

[oosik]

I have electric engagement on my riding mower. It's OK for a riding mower - no problems in the 17 years I've had it. The Kubota M6040 is a totally different story. Both 4WD & PTO are mechanical engagement. I don't think I can "feather" the 4WD engagement. It's either in or out. The PTO engagement can and alway is feathered into full engagement. It's a very nice feature that ensures smooth, gentile engagement of PTO implements.

 

[Agvg]

Hydraulic 4WD engagement is very old tech, no problem at all on tractors since probably the seventies.

 

[JasperFrank]

I can't even conceive of using a two wheel drive tractor, unless one's property was very flat. Having been somewhat use to two wheeled tractors, in an area that was flat, and then living in an area that was not so flat, and using an FEL on those not so flat areas, a 4 wheeled tractor is twice the utility of a two wheeled tractor. I would never consider a two wheel tractor any more. It very much just depends on the terrain, and snow seasons you are working with. For me, there is no going back to two wheel drive.

 

[goeduck]

Hydraulic 4WD engagement is very old tech, no problem at all on tractors since probably the seventies.

My 4WD is a lever by my heal. Is it possible in a runaway situation that I might be able to pull it up to engage 4WD? Maybe that is not what you are saying.

 

[LouNY]

Hydraulic 4WD engagement is very old tech, no problem at all on tractors since probably the seventies.

The nicest thing about many of them was they actually are in 4wd till you turn it off,
my branson 8050 takes power to turn it on, it also engages it automatically if you press both brake pedals at the same time.

 

[k0ua]

My 4WD is a lever by my heal. Is it possible in a runaway situation that I might be able to pull it up to engage 4WD? Maybe that is not what you are say8ng.

Not likely. You will never get the gears to mesh. Just exactly how the big tractors with their electric over hydraulic engagement works, I am not totally sure. There may be synchronizers at work here. Might be why it is not available on CUTS or SCUTS. Engaging 4wd on the "fly" has been available on our pickup trucks for several years, but remember it was not always thus. Could you put your 1958 power wagon in 4wd on the fly? I don't think so. Tractor technology at least as it relates to drivelines is pretty rudimentary and ancient technology. Except when you get into big expensive tractors.

 

[LouNY]

Not likely. You will never get the gears to mesh. Just exactly how the big tractors with their electric over hydraulic engagement works, I am not totally sure. There may be synchronizers at work here. Might be why it is not available on CUTS or SCUTS. Engaging 4wd on the "fly" has been available on our pickup trucks for several years, but remember it was not always thus. Could you put your 1958 power wagon in 4wd on the fly? I don't think so. Tractor technology at least as it relates to drivelines is pretty rudimentary and ancient technology. Except when you get into big expensive tractors.

Most of them are multiple disk wet clutches, many of the larger Ag ones use the hydraulics to disengage.
A 58 power wagon could be shifted into 4wd while being driven, most of them didn't have free wheeling hubs so they could be shifted any time as long as you weren't spinning.
Any 4wd truck if the hubs were engaged could be placed into 4 wd while moving.

 

[davidjmcclelland]

In winter while plowing there have been a few times when my glove caught on the lever and put me in 2WD unawares.
After the panic feeling subsides I put it back in. The panic is me thinking I have no clutch. It is that dramatic.
2WD is only for when I am mowing flat areas.