When to use four wheel drive?

[wagne223]

I'd be really careful about keeping 4x4 on clean pavement. There's usually no diff up front and it can put a ton of stress on the drivetrain.

If there was no diff on the front, you would not be able to steer.

 

[vvanders]

Yeah you're right, meant transfer case.

Either way not a great idea to run 4x4 on a surface where the wheels can't slip a little.

 

[dragoneggs]

Yeah you're right, meant transfer case.

Either way not a great idea to run 4x4 on a surface where the wheels can't slip a little.

Agreed! This applies to any 4x4 that I know of.

 

[wagne223]

Yeah you're right, meant transfer case.

Either way not a great idea to run 4x4 on a surface where the wheels can't slip a little.

Agreed.....nowhere in my post that you quoted did I recommend running 4wd on pavement.

 

[daugen]

I think the moral of this story is that for so many of us who learned perhaps erroneously that you used 4wd only in cases of real need,
just like our pickup trucks, we have been too cautious and perhaps missed out on safety.
I wouldn't even drive down the road on dry pavement in the "auto" modes of many of these new computer guided
transmissions. Always thought you should disconnect everything that wasn't needed.

and here to learn that my two 4wd tractors really should/could stay in 4wd on my small farm, since I'm on lawn and field only.
But.......when I mow roadsides with the cab Kubota, I have to remember to turn off 4wd. I forgot once and on the way home wondered what is all that
noise? Whirrings and whinings added to the normal hydro howl. Almost at the end of the lane, I thought oh no I know what it is...and stopped, pulled the lever up
and resumed with much less machinery noise.

what about running 4wd on the road at 15mph? Even if you don't care about your tires...
just wondering what those transfer cases were designed for
Lots of the big tractors have 40kph top ends now, to compete with the Europeans, but
could be comparing apples to oranges here, perhaps high speed versions have different style
gears, don't know. But I bet some one here does.

When I realized I had run a mile on the road in 4wd, I felt a little better knowing I had used synthetic lube oil
on the last change. Figured i must have heated something up pretty well in there, but maybe not.
I learned not to jump to conclusions based on my oldest tractor.

The transmission howl out of my Super A is remarkably loud, straight cut gears, but all the mechanics just smile and say
that's normal. Simply cannot imagine taking that ancient thing out on the road in top gear at full throttle.
So as much as I swear something is seriously broken in there (tractor runs great...) compared to my other tractors,
all that whining in 4wd may also be more of a worry than it need be.
Titan and Firestone sure like it...

 

[Grumpa Wally]

I use 4wd when the ground is soft while pulling a heavy grain drill, other heavy equipment or equipment that causes a significant drag on the tractor. My M7060HD12 has four wheel braking when both brakes are applied at the same time, otherwise it is two wheel braking. On gravel or dirt I don't run in 4wd when I am traveling at higher speed. I definitely hit the push button 4wd when I'm on inclines either dry or wet, better safe than sorry. Hope this helps.

 

[AxleHub]

And yet think how others would react to our 4wd concerns. 25 years ago I owned a AWD Ford Explorer. We now have many brands of AWD walk behind lawn mowers. And Subaru - since it began making cars, SUV, or trucks . . . aren't they all AWD ?

My point is. . . Being 4wd isn't as big an issue of concern as maybe we've made it to be. 4wd is very helpful, but it's not like "lock out hubs" on pickup trucks used to be in the 70s.

Now what I don't understand is. . . . Why some tractor owners experience much steering difference in 2wd vs 4wd ?

Now my Massey gc1715 SCUT has no difference in steering regardless of 2wd or 4wd. But my neighbor's j. D. X728 mower has a difference I'm told, and reviews of other tractor units often mention it.

 

[daugen]

And Subaru - since it began making cars, SUV, or trucks . . . aren't they all AWD ?

you bet, my Outback has amazing traction along with good Michelin tires. Sticks like a leech to the road.
I call it my poor man's Audi. Which also has remarkable traction.
In fact, many of the super high performance cars today have AWD simply because rear wheel drive can't provide enough
grip. Can you imagine an AWD Hellcat?
Or the new Hellcat RedEye with AWD. :thumbsup:
but I digress...

Hasn't there been a lot of improvement over the original 4wd mechanisms in tractors?
The early ones had those big transfer cases, now we have axles going through oil pans, all kinds of interesting engineering.
My understanding is that there are two different types of 4wd front transfer cases and one turns more tightly in turns.
but I'm sure there are more differences than that.

First thing I'm going to do this morning is check to see if my Kubota dash has a 4wd light, that green tractor.
I must be blind if it's there.

 

[PILOON]

Actually the answer is simple.

Only when rear differential lock fails to do the job.

 

[vvanders]

And Subaru - since it began making cars, SUV, or trucks . . . aren't they all AWD ?

you bet, my Outback has amazing traction along with good Michelin tires. Sticks like a leech to the road.
I call it my poor man's Audi. Which also has remarkable traction.
In fact, many of the super high performance cars today have AWD simply because rear wheel drive can't provide enough
grip. Can you imagine an AWD Hellcat?
Or the new Hellcat RedEye with AWD. :thumbsup:
but I digress...

Hasn't there been a lot of improvement over the original 4wd mechanisms in tractors?
The early ones had those big transfer cases, now we have axles going through oil pans, all kinds of interesting engineering.
My understanding is that there are two different types of 4wd front transfer cases and one turns more tightly in turns.
but I'm sure there are more differences than that.

First thing I'm going to do this morning is check to see if my Kubota dash has a 4wd light, that green tractor.
I must be blind if it's there.

So AWD and 4x4 are different in a subtle way. With AWD there's another some sort of coupling that can slip(to keep driveline from binding, think the case of why you have a differential but for the forward/rear tire sets) and some systems(high end Subaru, all Audis, etc) can adjust the amount of power front/back.

Running 4x4 on a surface with high traction puts a ton of strain on the transfer case as the front/back wheels won't spin exactly the same speed. Easy way to get a $$$ repair on your truck if you do it often enough.

Also, no need to imagine a Hellcat AWD, we already build one of those in the US and it's a Tesla P100DL . I've had a chance to drive one and it's straight up bananas. It's also a 3rd, different type of drive system with two completely independent front/back motors and an open differential in each.