4x4 Question

[broomjob]

I am in 4x4 24/7, (except on pavement) To me its all about safety, not wear and tear on the drive train. I would rather have rapair bills than rehabilitation bills. You flatlanders might get away with 2 wheel, but where I am (NH white mountains) being in 2 wheel means you are never more that a 45 degrees away from a very exciting downhill run.

 

[N80]

I leave it in 4wd most of the time. The only time I take it out is when driving on pavement or when I don't want to dig the soil up as much when mowing. With Ag tires on the front it really cuts the grass up when turning in 4wd.

I don't buy the argument that using 4wd causes any sort of accelerated wear. I suspect that 4wd system is made to last as long as the rear drive system with constant use. But, I also don't believe running it all the time necessarily adds wear to the tractor. I do think driving in two wheel drive until you have to put it in 4wd to keep going puts additional wear on the whole tractor. When in 4wd you don't need as much engine power to get the same task done (if traction is required) as you would in 2wd. In other words, straining the tractor in any way just in order to accomplish a task in 2wd is probably more likely to add premature wear than using 4wd all the time. Using 4wd also keeps the front drive components well lubed.

In any case, its up to the individual but I disagree with the notion that using it all the time accelerates wear to the tractor. That shouldn't be a reason not to use it anyway.

 

[Soundguy]

We need to keep in mind that whether the tractor is locked in 4x4 mode, or not, the gears and shafts still turn all the time anyway. The only difference is that stress resulting from slight differences in gearing between the front and rear is eliminated. Such stress results from a small amount of overspeed designed into the system, where the front tires are made to turn slightly faster than the rears, by design, not chance.

When the 4x4 is not locked in.. there will be no load on those front end components.. i.e. .. no driveline runup from different front / rear ratio. That equates to slightly less wear on the front end. I'm not sure I have ever seen a front axle drive shaft or front diffy break while in 2wd mode!! I've sure seem em crack or wrung off in 4wd and when in a bind.

For me, living in the hills of western PA, there is a safety margin that is increased by keeping the tractor in 4x4. When not in 4x4 braking is by the rear wheels only. If I have something in my loader bucket, going down hill can reducing the amount of breaking available to the rear tires. 4X4 mode gives me better control overall.

My comment specifically addressed this as a broad 'exception'.. I.E. If you need it use it. Hills would be a prime situation to use it.. better control and breaking. If you are gonna argue the point.. you have to be fair... as this specific instance, was mentioned. Gotta keep it apples to apples here.

If tractors had hubs that could be locked/unlocked like a 4x4 truck does, I would buy into the idea that taking the tractor out of 4x4 mode saves wear (and some tear) on the front end components. But since they don't, I guess I don't either.

The logic of your post states that since the tractors don't have lock in 4x4 hubs, then there is no extra wear.

From a physiscs point I can't buy that. If the front end is freewheeling vs under load, then there will be more wear while under load. I'd be hard pressed to believe otherwise.

Soundguy

 

[Soundguy]

I don't buy the argument that using 4wd causes any sort of accelerated wear. .

So you are saying that a dead axle freewheeling is not going to wear any system components any faster than when being worked in 4wd. Keep in mind we are refering to bearing and bushing wear, gear facing wear, shafts and fasteners.

Since when in 4wd,t he front axle will be driven, all front end components will be under extra stress of 'leading' the tractor, and when turning, they will actually be fiting the rears, which can be seen when grass or dirt scuffs to allow the oversped front to stay ahead.

That can't be anything but accelerated wear. As i said before.. I never saw a front drive shaft break while in 2wd use...i.e. when not under any load. I've seen plenty of them snap when in 4wd.

I'm not purporting drastic wear like the front end is gonna fall off in 'x' years.. I'm talking about absolute wear.. that is.. if you took a visual inspection of the parts, checked them with a mic... I'd expect to see more wear and wear in marks in a front end section that has .. say.. 2000 hrs of constant 4wd use, vs a front end section that had low/no 4wd use.


Soundguy

 

[ovrszd]

I leave it in 4wd most of the time. The only time I take it out is when driving on pavement or when I don't want to dig the soil up as much when mowing. With Ag tires on the front it really cuts the grass up when turning in 4wd.

I don't buy the argument that using 4wd causes any sort of accelerated wear. I suspect that 4wd system is made to last as long as the rear drive system with constant use. But, I also don't believe running it all the time necessarily adds wear to the tractor. I do think driving in two wheel drive until you have to put it in 4wd to keep going puts additional wear on the whole tractor. When in 4wd you don't need as much engine power to get the same task done (if traction is required) as you would in 2wd. In other words, straining the tractor in any way just in order to accomplish a task in 2wd is probably more likely to add premature wear than using 4wd all the time. Using 4wd also keeps the front drive components well lubed.

In any case, its up to the individual but I disagree with the notion that using it all the time accelerates wear to the tractor. That shouldn't be a reason not to use it anyway.

Sorry, but your front end driveline is not designed to last as long as the rear driveline, that's just simple physics. The manufacturers do not have to build it to last as long because it's not intended to be used as much.

Secondly, it requires more engine power to do a task in 4x4 versus 2x4, again simple physics.

I'll offer one last test to explain the stress you are putting on your tractor when driving around in 4x4. Put your tractor in 4x4, go out in the lawn or in the driveway or wherever you like. Turn the wheels to half lock or full lock or whatever degree of turn you choose. Drive until you have completed half a circle. Stop the tractor. Now with the engine at an idle, begin to move again gently and slowly. Whether you are HST or gear/clutch equipped, you will notice a significant resistance to movement. You will have to push harder on the HST pedal or lug down the engine more than normal when engaging the clutch to get the tractor to move out of it's resting position. Why is that???

It's because again you have the drivetrain stressed and what us Jeepers call "bound up". In Jeeps I have saw this stress so strong that the "drive" ujoint on the driveshaft will begin movement as much as 1/8th of a turn before the driven ujoint moves, twisting the driveshaft.

You can call that whatever you want. "Properly lubricating your front end parts." "Taking less power to do the same task." "Being safe." Whatever feels good in your mind. I call it undue stress on your driveline. I call it premature failure of driveline parts if done long enough.

Like Soundguy said, it's not like the front end of your tractor is going to fall off tomorrow or that you are destined to buy new frontend parts next week. We are just saying, it's unnecessary wear, plain and simple.

And as Soundguy said, when you need 4x4, use it. When you don't need 4x4, don't use it. Real simple. And again, your tractor will thank you!!!

Lastly, I don't have an owners manual over here with me, but will someone get out their owners manual and tell us what it says about using the 4x4 feature, when to engage, when to disengage???

 

[N80]

My point is that your argument on wear in a front drive system is kind of like saying that if you don't use a tool it will wear less than if you do use it. That's kind of obvious. I'm not saying that using it doesn't result in _any_ wear.

My point is that the front drive train in these tractors is designed to be used and I suspect it is designed to stand up to constant use for the life of the tractor. Taking it out of 4wd in order to 'save' the front drive system simply doesn't make any sense. It was made to be used. Using it at times when it is not 'needed' (low stress, good traction) is unlikely to add enough wear to it to have any impact on the useful life of the tractor. And it is _not_ analogous to the 4wd systems in most light trucks and SUVs. Most of these systems are made for occasional offroad use. I dare say this is hardly true of any decent tractor.

My other point, and I thought it was clear, was that if you are only engaging 4wd when you lose traction, then you are likely adding unnecessary wear to other parts of the tractor.

And citing that you've only seen front drive shafts break when in use is kind of self evident too. Very few tools break when they aren't used. Unless you see front drive shafts breaking during typical '2wd' type use, then there isn't much of a point there. If someone breaks a front drive shaft they are either abusing the tractor or they are using it in a situation that demands 4wd.

It really just comes down to defining when it is needed. That is up to the individual. My final, and main point is that constantly going in and out of 4wd for the sole reason of protecting the front drive system is probably pointless and the only likely _eventual_ outcome of such diligence would be pristine front drive line in an otherwise worn out tractor.

 

[N80]

Ovrszd, what evidence do you have that the front drive lines are not designed to last as long as the rest of the tractor? Is this true for all tractors?

Also, with my L4400 there is absolutely zero binding, as you describe. And before you say anything, I'm quite familiar with 4wd systems and the phenomenon you are describing. In fact, I've never owned a vehicle that was not a 4wd. I've spent a lot of time driving offroad in everyhting from Willys Jeeps, IH Scouts, the old full sized Jeep Cherokees, The big AM General pick up, Chevys, Fords, Nissans, Toyotas. I've felt binding while turning at full lock in many of these (my current F150 being by far the worst of any of them) but I can assure you, if it is happening in my Kubota, I can't tell.

But I think it really all comes down to someone producing evidence that the 4wd systems in typical CUTs are not made to last as long as the rest of the tractor. If that is the issue then yes, we should all be carefully conserving our front drive lines. But I don't buy it for a second and won't until I see proof. When I do, I'll be the first to start worrying that my front drive line will go before the rest of the tractor and I'll do as you advise.

 

[N80]

And I disagree with your simple phyiscs. If I'm reving and spinning to get up a slippery hill vs doing the same thing at idle speed while in 4wd, then I'm not stressing the engine as much. Certainly not more in any case.

 

[wilkesland]

Lots of opinions, folks vary. I don't own anything but hills and never take my tractor out of 4 wheel drive. But then, it is never on pavement either. I've gotten stuck enough times with the tractor in 4 wheel drive that it is not worth it to me. I prefer to keep it in 4 wheel drive to avoid as many problems as possible. Similarly, I almost always put my pickup in 4 wheel drive if I think it is going to be needed, which is everywhere on my property other than my drive. If I owned flatter ground, I probably wouldn't have payed the extra for a 4 wheel drive tractor.

Some argue that it is unnecessary wear on the tractor, and for them, they are correct. That using 4 wheel drive causes wear is not disputable, what is disputable is the the "unnecessary" part, and that of course varies with the individual. I'm using the tool I purchased exactly the way I want to use it.

Barry

 

[BillyP]

I don't understand what all this bickering is about

If you "need" your tractor in 4WD all the time then leave it there. No one ever said any different.