FWA is not 4WD

[Doc_Bob]

After reading the thread here on 4WD advantages/disadvantages, I took my New Holland TN70A and did some work on some very wet and sloppy ground. I went in 2WD then scooped up a full 72 inch bucket of wet, heavy rotted horse manure, then my rear got light and was spinning my rear wheel with the diff locked. Of course, slipped it into FWA. I got out farther due to FWA, but still too much weight, not enough traction, got stuck, had to dump the load and then moved out of harms way (getting stuck) using FWA. So what did I learn?

FWA is not 4WD. I think when I talk about 4WD, my tractor (and I suspect everyone else is in the same boat), does not have "real" 4WD but FWA. I now understand the difference.

Bob

[N80]

It is largely a matter of proprietary terms. There is no accepted standard terminology regarding the naming of these front drive systems. For Kubota, all of their tractors with a front drive train are called Four Wheel Drive or 4WD. Other makers use different terms. I suspect that my tractor is much like yours though, the front diff is open so the tire with the least traction will spin and the other tire will not. In a technical sense, such a '4wd' tractor is really '2wd' but again, you get into semantics. No one ever said that '4wd' means that all four wheels are powered all the time. In most cases it simply means that power can be applied to all four wheels.

If '4wd' means to you that all four wheels always have power all the time, then virtually nothing is "real" 4WD outside of some monster Ag machines and some skid steers. There are some standard Ag and maybe some utility tractors with diff locks for front and rear.....I suppose you could call them "real" 4wd.

I consider my Kubota to be "real" 4wd because it has a sticker on it that says "4WD". I just know what Kubota means by "4WD".

[Billy_S]

Mechanically, I have no idea what the difference is between 4WD and MFA but, being in the tire business, I was always told that 4 wheel drive tractors have the same sized tires on all four corners while mechanical front assist tractors have larger rear tires.

[roxynoodle]

Originally Posted by Billy_S

Mechanically, I have no idea what the difference is between 4WD and MFA but, being in the tire business, I was always told that 4 wheel drive tractors have the same sized tires on all four corners while mechanical front assist tractors have larger rear tires.

You are correct. For a true 4wd tractor look at the Steigers.

[AndyMA]

Originally Posted by Doc_Bob

I took my New Holland TN70A and did some work on some very wet and sloppy ground. I went in 2WD then scooped up a full 72 inch bucket of wet, heavy rotted horse manure, then my rear got light and was spinning my rear wheel with the diff locked. Of course, slipped it into FWA. I got out farther due to FWA, but still too much weight, not enough traction, got stuck, had to dump the load and then moved out of harms way (getting stuck) using FWA. So what did I learn?

FWA is not 4WD. I think when I talk about 4WD, my tractor (and I suspect everyone else is in the same boat), does not have "real" 4WD but FWA. I now understand the difference.

Bob

Bob, On your TN when you engage the differential lock does it lock both axles or only the rear. Also is it a mechanical lever or a dash electrical switch? On my TN75D, it's a dash switch and it locks both axles.

Andy

[jeffinsgf]

If you think you can't get stuck with "true 4WD" -- think again. 4 wheels spinning in the mud just buries you deeper faster. The hope is the one of the four corners can get some traction. If it can't, you're stuck.

[Glowplug]

Originally Posted by jeffinsgf

If you think you can't get stuck with "true 4WD" -- think again. 4 wheels spinning in the mud just buries you deeper faster. The hope is the one of the four corners can get some traction. If it can't, you're stuck.

What about factors like weight distribution over the axles, larger traction footprint, etc.?

[jeffinsgf]

Originally Posted by Glowplug

What about factors like weight distribution over the axles, larger traction footprint, etc.?

It is all going to help, but I have seen true 4WD tractors (the ones with all the same sized tires) and true 4WD skid steers, and true 4WD trucks all stuck to the point a wrecker was needed. My point is, in the situation Bob was in -- that is a fully loaded bucket and no traction at any wheel -- having all 4 wheels spinning might not have been his salvation. If you get in a real slough of mud, you're just plain stuck. Don't get me wrong, I would NOT be without FWA. It or 4WD will get you out of most spots -- but not all.

I don't want to start the next 17 page thread on this subject, BUT...

Has anyone here with an FWA tractor that has a differential lock been stuck to the point of having the FWA locked in and engaged the differential lock? Does the front lock up, too, or just the back? I have, but the second I tapped the diff lock, I popped out of the spot I was in, so I couldn't tell if the front locked up, too, or not.

[weesa20]

Y'all crack me up....FWA...what the heck is that....I have put a load heavy enough to lift the rear tires of my GC of the ground (without ballast) and have driven it a short distance using just the front tires (back tires were not even on the ground and the bucket was an inch or two in the air)...so does this mean I can now say I have a front-wheel drive tractor with rear wheel assist?

Almost all vehicles that we call "four-wheel-drive" are really just two wheel drive or three wheel drive (in the case of one locking and one open diff) and it just depends if you have the ability to drive either rear wheel in addition to either front wheel or two wheels and one other wheel...the only "true" 4WD are machines that all four wheels are locked all the time without diffs and have to be skid steers or articulaitng machines because otherwise they won't turn.

My GC2300 is a 4wd machine...it says so on the side (at least by the generally accepted definition in this industry)

Many CUTS have lockable front and read diffs...just depends on the machine.

W

[charlesw]

Originally Posted by jeffinsgf

4 wheels spinning in the mud just buries you deeper faster. The hope is the one of the four corners can get some traction. If it can't, you're stuck.

There is the infamous story around here of the the 8WD tractor that got stuck. So, they brought an 8WD in to get it out. It got stuck, too. They brought another 8WD in to get those out. It got stuck! Then they brought a dozer in to get everyone out. I hear that it was quite a sight to see (and a huge attraction locally!). Those would be BIG 4WD tractors with duals front and back, of course.