4x4 Question

[sandman2234]

With few exceptions, I think the original question has been answered the same.

Two wheel drive until you need it, and then only on soils that will allow safe spinning of the tires. On anything harder than packed clay, ALWAYS disconnect the front wheel drive, especially if you are loading a bucket or other device that loads the front end with weight.

There are certain exceptions to this rule, such as my lawn mower. It is 4 wheel drive continously, and the only way to change that is with a wrench to disengage one or both drives. It is hydraulic drive, one motor to each axle, so falls under a different class, dispite the fact that it is probably larger than some of your tractors...

The fact that a person operates his own particular vehicle in 4wd full time, is his own decision, and unless he changes tractors every few years, he will suffer for that decision. Hopefully I won't be the new owner of one of those used tractors.
David from jax

 

[CDsdad]

This is straight from my M/F 1533 manual which also covers the 1540, 1547, and 1552.

Page 46 under FIG. 68:

When front axle is engaged, ground speed of front tires will vary from ground speed of rear tires. This is to assist when four-wheel drive is selected.

For this reason, the front axle must be disengaged when the tractor is transported or operated on a hard, dry surface. Failure to do so will result in rapid wear of front drive tires and possible driveline damage.

IMPORTANT: Always disengage front drive axle when operating in conditions with minimal wheel slippage (DRY OR HARD SURFACES).

IMPORTANT: If tire replacement is necessary, identical replacements must be installed to maintain correct front/rear axle ratio.



I typed that as I saw it in the book except I don't know how to italicize the IMPORTANT statements as they are in the manual.

So having a Massey Ferguson, I will follow the recommendation in my Massey Ferguson owner's manual and leave you gentlemen (and ladies if you're here) to debate the burning question at hand. I got to figure out how to italicize.

 

[Timber]

Oh, you are talking about a full-time 4x4 system like was introduced in the mid 70s?? If so, it's using the front and rear axles equally. The T-case is just a splitter like a rear axle splits power to each wheel. Just like the tandem drive on your semi splits power to each rear axle and the one with least traction spins out until you lock the splitter.

There are some systems on new trucks that are traction sensitive like larger Ag tractors use. That's what was referred to back a few posts on this thread which engages and disengages depending on traction needs.

I have had a couple full-time 4x4 pickups. Very dangerous to drive on slick roads because you are unaware they are slick until you tap the brakes, then life changes quickly.

I didn't realize your driving experience or history were in question. Sorry if you felt offended by my questions. I just thought you had something that I wanted to learn about.

Please do not miss understand me. I state my experience to give me some credibility and by no means an authority and take no offense, there are a number of people that have misguided faith in the 4 wheel drive capability of there vehicles

The 4 wheel drive system is a standard feature in most GM trucks for several years now. It is electronic and controlled by the computer' the options are
2 wheel high
4 wheel Auto
4 wheel high
4 wheel low
It is the same feature that a lot of sport cars use full time employed into a truck application. very handy feature. It is not the quad track of the late 70s. The computer has changed everything in that respect

 

[cp1969]

italicize

Just type left bracket, i, right bracket in front of the word you want italicized and left bracket, forward slash, i, right bracket behind it.

 

[N80]

Hmm.. I havn't seent hat spelled out here.. I don't think the front axle is any less durable than any other part of the tractor.. Soundguy

Well, here is the quote I'm referring to:

"Sorry, but your front end driveline is not designed to last as long as the rear driveline, that's just simple physics."

 

[CDsdad]

Thank you cp1969.

 

[ovrszd]

Well, here is the quote I'm referring to:

"Sorry, but your front end driveline is not designed to last as long as the rear driveline, that's just simple physics."

I'll stand by my statement. Refer back to my description of the moving/wearing parts involved between your rear axle and your front axle. Or get out your parts manual and look for yourself.

Also, I think we have already determined that the L4400 has traction sensitive drive which eliminates the "binding" effect of MFWD. That explains why your manual doesn't warn you about driving excessively with it engaged. So for the tractor discussion, we still need to keep the tractors with traction sensitive systems separate from the MFWD tractors. So far in this discussion N80 is the only person I've heard say they have a traction sensitive system??

 

[ovrszd]

Please do not miss understand me. I state my experience to give me some credibility and by no means an authority and take no offense, there are a number of people that have misguided faith in the 4 wheel drive capability of there vehicles

The 4 wheel drive system is a standard feature in most GM trucks for several years now. It is electronic and controlled by the computer' the options are
2 wheel high
4 wheel Auto
4 wheel high
4 wheel low
It is the same feature that a lot of sport cars use full time employed into a truck application. very handy feature. It is not the quad track of the late 70s. The computer has changed everything in that respect

Timber, your description of your truck system is a modern version of the full-time drive system of the 70s. It has no connection to your vehicle computer other than to trigger lights in the dash and engage the front axle disconnect if so equipped.

When in 2 wheel high, that's all the drive you have.

When it's in 4 wheel auto it is functioning as the previous mentioned full-time drive system splitting power to each axle. Similar to your semi rear ends when the power divider is unlocked. To prove this, jack up either end of your truck until both front or rear wheels are off the ground. Engage 4 wheel auto and try to drive off the jack. It will just spin whichever axle you have jacked up and won't move the vehicle.

When it's in 4 wheel high it is locked in 4 wheel drive and demands equal rotation of the front and rear driveshaft. Similar to your semi rear ends when the power divider is locked. If you jack the truck as described above, it will drive off the jack. This is what your B7800 has when you engage MFWD with the lever.

When it's in 4 wheel low it's locked in 4 wheel drive but is operating in low range of the T-case.

 

[Timber]

Well regardless of the technicality's the bottom line and the bigger picture is, It is far better to use your 4 wheel drive on your tractor than not if there is any question as to if you should or not. I would rather see someone use the 4 wheel drive full time than to not use it when they should and get themselves in trouble. You are never going to hurt your tractors 4 wheel drive system as most everyone uses there tractor off road 95% of the time. Then to compare the use of your 4x4 anything to your tractor is a total non issue because the application is completely different. The ground speed and the surface are the factors that damage a 4x4 and that only in abuse or deterioration do to time and wear. If you use a loader for anything regardless of the application and not use your 4 wheel drive is just foolish. The moment you put wt into the bucket or on forks you pivot over the front axle and take the load off the rears and if your front axle is free wheeling your in trouble.

 

[N80]

Also, I think we have already determined that the L4400 has traction sensitive drive which eliminates the "binding" effect of MFWD. That explains why your manual doesn't warn you about driving excessively with it engaged. So for the tractor discussion, we still need to keep the tractors with traction sensitive systems separate from the MFWD tractors. So far in this discussion N80 is the only person I've heard say they have a traction sensitive system??

I did not say my tractor has a traction sensitive system. I have no idea what that is. The L4400 is an extremely basic tractor. Gear drive. Economy model. If it has such a system it is not listed in the specs, brochure, owners manual or web site. Such a system might be inherent to the Kubota bevel gear front axle design, but they don't say anything about it.

I tested my tractor again yesterday, just to make sure I was missing something, and there is no appreciable binding that I can detect. I'm sure there is some, but you can't feel it. If the soil is loose and you turn tightly you can see the outside wheel dig a bit, but you can see that in 2wd as well.

I'll summarize my feelings on this:

My tractor is sold with a front drive system.

Kubota does not suggest anywhere at any time that this part of the tractor is any less durable than any other part of the tractor. There is no documentation that there are any conditions in which it cannot be used.

This tractor is designed to be used in conditions that could require always using the front drive system, even for the life of the tractor. In other words, this tractor could be used for loader operations every day of its life. In this regard, it is highly improbable the Kubota has designed it with a specific area of the drive train incapable of enduring such use.

Leaving it in 4wd during operations in which 2wd is suitable, will lead to more wear than if it were not in 4wd. But I suspect such wear is so minimal as to be trivial.

Using the front drive train at any time the owners manual for that specific tractor specifically says not to, will clearly accelerate the wear on the system.

Question: Is the bevel gear front axle system unique to Kubota?