Is Full Time Use of 4WD a Problem?

[/pine]

My Brother leaves his L3240HST in 4wd all the time. When I get on it the first thing I notice is it's sluggish movement. I usually have to back up or turn the steering wheel back and forth while moving to get it out of 4wd. As soon as I do, the tractor moves more freely.

Almost all CUTs are designed with different ratios in the front versus rear. If operated on solid footing they are bound up at various times depending on that ratio. My Brother's tractor is geared so the front tires travel at a slightly faster ground speed than the rears. So as soon as it starts moving it binds and takes more power to move.

I'm not dictating operational behavior to anyone. It's your tractor. With that said, driving around in 4wd all the time will increase wear and shorten the life of the tractor's powertrain as well as the tires, more front than rear. With that said, is it significant?? Probably not. But it's unnecessary wear. And as I already said,,, it's your tractor.

My uses are severe and mostly in steep timber. I am on a first name basis with my 4wd lever.

From what I have about tire size and rolling circumferences is...in neutral on flat ground the tractor should roll freely (no binding from different ratios)...

 

[ovrszd]

From what I have about tire size and rolling circumferences is...in neutral on flat ground the tractor should roll freely (no binding from different ratios)...

Hmmmm, if you mean in 2wd, yes. If you mean in 4wd, not necessarily.

Not if it's setup with differing ratio. And his is, as are most CUTS. i believe Kubota uses a 1.5% percent ratio variance but someone can correct me if that's not the right number.

It's easy to check your tractor. Sitting on solid footing, in 4wd, front tires pointed straight forward, drive forward 50 feet. Stop and disengage 4wd. Does the lever move easily? If equipped does the 4wd light go off immediately?? If the lever is hard to move (mechanical engagement lever) or if the light does not go out, the tractor is bound up because of this differing ratio.

To know for sure that the tractor has truly disengaged the front axle, while still stopped, cramp the front tires to left or right, then move forward and observe the tractor, it'll be easy to tell if it's still in 4wd or not.

A description of a Mechanical 4wd Engagement Lever would be a lever that's connected directly to gear that it slides into 4wd or out of 4wd depending on lever location. If you tractor has that type of engagement, and it's ever difficult to get it out of 4wd, at that given time, your tractor is "bound up" and is causing stress and wear on it's components as well as requiring more power (fuel) to perform it's given task.

My M9540 does not have Mechanical Engagement. My lever activates a spring loaded shifting fork that will move the required gear into and out of 4wd when all stresses are released and the drive system is not "bound up". If driving forward in 4wd and you shift it to 2wd and do not change the load or turn the front tires right/left, it will stay indefinitely in 4wd because it's "bound up". It will only disengage by stopping and/or backing up or turning the front wheels right/left while moving.

Since this conversation includes such a wide variety of setups, it's important to know what type your tractor is.

 

[taborekle]

I would (and do) leave it in 2WD unless necessary for 4WD work. One thing about our Kubotas is that you can really crank the wheels to very sharp turning angles, which is difficult to do when in 4WD mode, as there is more binding. There is also the problem that if you are doing front loader work in 4WD and the loader is very low (like when trying to uproot a tree by the root) and the front wheels come off the ground, in 4WD mode they are still turning. Then if the bucket looses grip on the root, the bucket can come up so quickly that it will drop the front wheels on the ground, which in turn can tear up the front gear train. My friend bought a John Deere that had a non-functional front end drive system on his 4WD tractor (ebay). When examined, it was felt by the mechanic that this is the result of dropping the front wheels on the ground in 4WD mode.

Leave it in 2WD unless needed.

 

[LD1]

Mine stays in 4wd full time with two exceptions:

1. Driving on road or straight and flat hard surfaces unloaded for extended periods.

2. Mowing or bushhogging where I use brakes to steer.

 

[sd455dan]

Exactly, I don't think a lot of people realize that. I don't doubt there is some small reduction in fuel usage by going to 2WD, but I can't see how it would be much. And if you had a lot of slippage in 2WD it might even be a negative savings. Of course your 4WD equipped truck is a different story, with the various hub decoupling schemes, in use today, all of the running gear is decoupled and does not add to the friction load on the vehicle. But tractors, not so much.

Actually in my case the Dodge 3500 and my Rhino are in essence the same: in 2 wheel drive both spin front axles and the front drive line
In 4x4 both lock front and rear drive shafts together and on hard surfaces both hop the front tire(s) on turns. I have read that putting front hubs on the HD dodges is worth about 1 to 2 mpg when unlocked on the highway which isn't worth it for over a $1000 buy in

 

[/pine]

I think we've reached a general consensus on the topic...but for the record I will repeat my MO...
If I am running in anything but low gear (which is about 2% of the time) I run in 2wd...the last thing I want to do is start down a grade with a bucket of gravel and THEN remember to engage 4wd...!

...I went through the ratio dilemma when I was looking for replacement tires (that don't exist)...!

 

[9973720wb19]

so my advise is the heck with worrying about hurting the tractor. Safety First! I mostly use 2wd but use 4wd whenever I need to, or I think it would be safer to do so. I can get a new tractor.

 

[RalphVa]

I only take mine out of 4wd if going on hard pavement very far. Otherwise, it's a serious safety issue taking it out of 4wd. Without 4wd, only have brakes on rear wheels. Not good going down hill.

Ralph

 

[RBA50]

"Must be a Reason . . ."

So, what's the reason? "I dunno" doesn't count.

As I said, there must be a reason. I didn't say either of the manuals explained that reason. :confused3: And your tractor may be different, Mine is a B2320 HST.

It may be related to the other warning in the WSM about not using both wheel weights and liquid ballast in the rear tires due to possible transmission damage. May not be. Only the Kubota technical writers knows why they put the warning about not loading the front tires in BOLD Print, preceded by IMPORTANT on page G51 of the WSM.

IMPORTANT
Do not fill the front tires with liquid.

In the owner's manual (B2320) Page 44, under Ballast

!Caution
To avoid personal injury:
Additional ballast will be needed for transporting heavy implements. When the implement is raised, drive slowly over rough ground, regardless of how much ballast is used.
Do not fill the front tires with liquid.

Or maybe the Devil (lawyers) made 'em do it. My guess is they think the tractor may be damaged. I just believe that if they went to all trouble of putting the warning in the manuals, it's for a good reason. YMMV

 

[ovrszd]

As I said, there must be a reason. I didn't say either of the manuals explained that reason. :confused3: And your tractor may be different, Mine is a B2320 HST.

It may be related to the other warning in the WSM about not using both wheel weights and liquid ballast in the rear tires due to possible transmission damage. May not be. Only the Kubota technical writers knows why they put the warning about not loading the front tires in BOLD Print, preceded by IMPORTANT on page G51 of the WSM.

IMPORTANT
Do not fill the front tires with liquid.

In the owner's manual (B2320) Page 44, under Ballast

!Caution
To avoid personal injury:
Additional ballast will be needed for transporting heavy implements. When the implement is raised, drive slowly over rough ground, regardless of how much ballast is used.
Do not fill the front tires with liquid.

Or maybe the Devil (lawyers) made 'em do it. My guess is they think the tractor may be damaged. I just believe that if they went to all trouble of putting the warning in the manuals, it's for a good reason. YMMV

I agree. I'm fairly mechanical and have thought about this subject a lot. Ther's definitely a reason Kubota has those warnings. There is a single component or possibly multiple components that they are trying to protect. It's possible that adding fluid in the fronts, for example, puts that component close to it's failure point and they want to avoid that. By adding the warning statement they are covered if there's a warranty issue and the warning was not heeded.

My M9540 has adjustable front wheels. Has a warning about maximum track width. The maximum width is wayyyyy less than what could be achieved by reversing the cupped centers. Again, there's a componet/components that they are trying to protect. I'm not going to reverse my centers and push the width beyond what's recommended just to see which component they are worried about!!!