No

 

I only use 4WD when I need it too. But I’ve never seen one damaged by full time use. I didn’t see that in the manual. I’ll look again. It is hard on it on hard surfaces since it doesn’t slip. But I’ve never seen one fail.

 

Yes it can. Too much weight and not enough slip can bind up the drivetrain. This can cause damage. It even says so in the manual. Use 4WD when needed, especially if not on terrain that allows some slip.

 

Yes it can

X2 on what dieselshadow said.

What they said!!

 

X2 on what dieselshadow said.

I only use 4x4 when needed for traction loading the bucket, pulling boxblade, or muddy soft ground here. Should be used climbing/depending a hill, this ties all 4 wheels to brakes.

 

Only use the 4x4 when you need extra traction....there is slippage in ratios between the front and rear not much but you don't need that stuff turning unless you're loosing traction.....24 years without having to buy an axle....

 

As several others have said, only engage 4x4 when needed. Machineryman gave the reason why running in 4x4 all the time can tear stuff up, so I'll explain further:

there is slippage in ratios between the front and rear

In other words, the front and rear axles don't turn at exactly the same speed, due to factors like manufacturing tolerances and amount of wear on the front tires versus the rear tires. In 2wd this is no problem because the rear axle is driving the tractor and the front axle and driveline is just a long for the ride, since although the front driveshaft may be turning, it is not connected to anything internally.

In 4x4 both axles are mechanically locked together. If one of them wants to rotate slightly faster than the other then something has to give way to allow that to happen. There are only two things that can give: either the wheels spin out slightly, or, something breaks. Now this won't happen instantly, you can roll along a short ways before there is enough stress built up in the driveline to worry about.

Basically, if the surface you're on doesn't allow the wheels to spin some, don't leave your machine in 4x4.

 

I run a boatyard with a rough gravel lot where we store and work on numerous boats. Our old JD 4400 has been through at least 2 front differential pinions and driveshafts because the employees love to leave it in 4WD all day long. You'd think gravel would allow enough slippage to protect the drive-trail, but it really doesn't and over time you'll pay for it. The last round of repairs I did myself, but even so it cost upwards of $4k in parts. Disengaging is so much less expensive!

 

also you don't want to be under full power and make hard turns, this compounds the stress. Running the tractor on hard surface at high speed will also do a number. Learning how to properly use the assist takes a level of skill.

 

Only when needed.

 

If you understand proper ballast then you want have too much weight of the front end pushing down in the ground. Mostly on larger tractors say 50-60 or better on solid ground they don't use as much 4x4 and it's not a factor in using front end loader as this should take the weight off the front. Now using a bucket expecially with the teeth as a bulldozer will work a number on the 4x4....not so much on dirt but on logs, stumps and solid things.

 

The real 4x4 JD tractors large have the same size tires in front as rear. This is an assist with the subcompact and compact tractors.

 

I disagree on this. Your truck has the same size tires all around, and if it's 4x4 the manual will say you shouldn't run in 4x4 on hard surfaces either. Does that make it not a "real" 4x4 truck? No, of course not.

Now if said truck is AWD that's a different story.
Anything that is 4x4 and can run all day in it on any terrain generally uses the term "all wheel drive" and such a system will allow for differences in front vs. rear ratios by utilizing a differential between the 2 axles to allow for slip.

As for that term "assist" or "front wheel assist", I read that the name came from a conversion kit offered in the 1950's (?) to add front wheel drive to a 2wd tractor. Apparently some of these kits simply drove the front axle at some random speed with no attempt to match the rear axle speed whatsoever, hence the term front wheel assist.

 

Hmmmmm..... My unpaved driveway has one section that is so steep that if I'm not in 4WD, I can end up accelerating with the rear wheels skidding on the surface. That's a pretty dangerous situation that is easily fixed by having 4WD connected. So I have kept it in 4WD 100% over the past 7 years with no apparent issues. No pavement anywhere. I need to drain my front axle and see how the lube looks.

OP: Good post!

 

Hmmmmm..... My unpaved driveway has one section that is so steep that if I'm not in 4WD, I can end up accelerating with the rear wheels skidding on the surface. That's a pretty dangerous situation that is easily fixed by having 4WD connected. So I have kept it in 4WD 100% over the past 7 years with no apparent issues. No pavement anywhere. I need to drain my front axle and see how the lube looks.

OP: Good post!

DanMc, what will you look for when you drain the front axle lube? Metal shavings? Signs of water? Like you, I am regularly on steeps. One is 17°. Going down can be unnerving. Going up with an implement is marginal without a lot of weight in front and 4x4 And dry ground.

 

 

Thank you all for the comments. I’ll be up at the farm today an will check the operators manual for JD recommendations on the topic.

 

I believe that the terms FWA and 4wd are used interchangeably but your tractor is 4wd. I've read on this site that the front drive leads the rear by a certain percentage which makes it even more important to use 4wd only on low traction surfaces.

 

I don’t use 4wd on dry pavement or other high traction conditions. But , if it’s even questionable if it’s slick I use 4wd.

 

I searched on AG tractor wheel slip and this was the first result. I haven't looked at manuals for large tractors with the same size tires on front and back or duals on the front, but I don't think the tires on compact tractors rotate at the same ground speed. On a tractor with 4WD that isn't meant to operate in 4WD all the time the front wheels have to turn at or slightly more MPH than the rear tires. That way they are pulling the tractor, if they turned slower than the rear tires once you got some traction at the rear the front would be pushed by the rear. I looked in my 3039R and it said to use 4WD for improved traction on difficult ground conditions. I take that to mean don't use it all the time.

4WD or not the link says tractors and tires should be maintained to optimize wheel slippage at 10% to 15%.
This is from the paragraph after the chart
"Slip also provides a safety valve against shock overloads that could damage the power train; some wheel slippage is needed to reduce wear on the power train"

This is at the end of the page
Adjusting Wheel Slip
If excessive slippage occurs (greater than 15%), you may need to:

• add weights (iron and/or fluid in tires),
• change the air pressure,
• add duals, or
• purchase new tires, if they are heavily worn.

If slippage is less than 10%, you should remove weights and check the tire pressure.


Optimize Wheel Slip to Save Fuel – Farm Energy (extension.org)

 

My 3039r manual also says to use 4wd to get four wheel braking. I agree with the others that say take it out of 4wd when turning if you can.

 

@arlen the front tires should not turn slower than the rears.
I took a screen shot of the 6410 manual and the front tires should over speed the rears between 1.5% to 5%.

 

You’re right of course…I had that backwards. The idea is the front pulls the rears into the track. That’s because most of the tractive force comes from the rears. I wasn’t thinking clearly this morning!

 

Due to size, front tires will wear faster than rear...like wise your ratio to the ground will change...probably not anything significant on dirt but on concrete/ashpalt real hard surface will make a difference.

 

Apparently there is some confusion of terminology on my part. My manual makes no reference to “4 wheel drive or 4x4”. The term used is “Mechanical Front Wheel Drive (MFWD)”. No prohibition on its use except for on pavement. The manual answered my question. But now is the question, what’s the difference?🤪

 

@Akovia I looked at my manual again and you are correct, I called it 4wd but the manual says mechanical front wheel drive.

If you use ground engaging implements on a tractor with MFWD and the soil is not hard then you won't bind or stress the front axle when you use it with difficult ground conditions.
If you use MFWD on a lawn and the rear tires don't spin the front tires will spin on the grass because of the designed in overspeed and not hurt the front axle.
If you are on hard/packed ground or driveway/gravel road and you need MFWD because of the implement, then difference in speed between the front and rear axles will cause stress on the driveline. You won't have tire slip to give a safety valve to prevent driveline damage.

 

I think I will discover that there are times when MFWD is not called for. Thanks again for helping me understand this.

 

I didn’t think engaging the 4WD lever on my 1025R locked the front into a full time pulling 4 wheel drive. That on sharp turns the front tires didn’t pull the same. That’s what the little locking lever depressed with the left heel did. You can still turn pretty sharp in 4WD so one wheel has to speed up or slow down. If the diff lock is engaged, it’s almost impossible to turn. Even if the front wheels turned are full lock, it still goes straight. The front wheels don’t pull the same even in 4WD. I’m on my second 1025 and have never had a problem with front binding up. But they do scoot turning on hard ground.

We have an AWD Denali which works great for traction but I miss the ability to turn it off and to select 4WD low range.

 

My understanding is that engaging 4wd does lock the front and rear driveshafts together but both the front and rear axles have differentials so you make turns. I have verified this by inadvertently dropping a wheel into a hole so one front wheel and one rear wheel don't have any ground pressure. The two unloaded wheels turn but the tractor doesn't move until the rear differential lock is engaged.

There can still be strain on the drive train even with the two differentials if 4wd is engaged and there's not enough slippage. More than once, I've had to either drive in reverse or make an opposite turn to unload the strain enough to disengage 4wd. I only use it as necessary because I don't need to stress things all the time.

 

I think the difference between 4WD and MFWD is that 4WD is 2 axles geared the same to limit binding. MFWD is 2 axles with different ratios accommodate the different diameter tires. I believe Deere uses the term "lead/lag" to measure the allowed % difference between the axles, which is usually 3%-5%.

AWD usually has a clutch between the 2 axles to prevent binding. My Subaru has 60% front, 40% rear gearing. Imagine the bind that would cause at 65 mph!

 

My Subaru has 60% front, 40% rear gearing. Imagine the bind that would cause at 65 mph!

Gearing? I think you mean torque bias, as in 60% of the torque out of the transmission goes to the front and the remainder to the rear. There's no way there'd be a 20% speed difference between front and rear axles... you'd be doing a burnout everywhere you went 😂

 

To further confuse everybody, my Escape has what is called 4WD in the owners manual. However, it goes on to specify that the computer reads the rear wheel traction requirements 200 times per second and applies power to the rear wheels as needed. So, it is basically a front wheel drive with help from the rear when needed. I have to admit it works really well. It is completely transparent to the driver. But I wonder if AWD would be a better term for it.

 

So not sure about your Escape but for awhile Ford Explorers had a 4wd Auto mode (I know my 2000 did), and it worked similar to what you describe except for the front axle. It was NOT AWD in that there was no center diff. When the computer engaged 4wd for however long it needed which could be a pretty short time the front and rear axles were locked together and operated just like a standard 4WD (sometimes called part-time 4WD).

Interesting thing about that Explorer because of how this system operated it meant that the front hubs where always engaged (no locking hubs or even auto-locking hubs), so not great for MPG or maintenance when 2WD. Also my 2000 had selections for 4x4Auto, 4x4Hi, 4x4Lo. I believe older models had 2x4, 4x4Auto, 4x4Lo, but people really did not like not having a proper 4x4Hi mode and you really did not need 2x4 with the way 4x4Auto operated.

Another thing that is not well documented about the 4x4 on the explorer is that it would also engage 4x4 if it detected WOT.

Now I believe Explorer's are actually AWD and unibody too.

 

We also have an 2013 Explorer, but it is front wheel drive only. 4wd was optional. Current models are rear wheel drive with 4wd optional.

 

Not wanting to hijack a different, excellent, thread,(Might be looking at a new 1025r axle.) I have a question about a topic raised there.
The OP had damage to front axle gears, bearings, and the axle itself. Mentioned several times was “always running in 4x4”. Those folks seem to think it is a bad idea.
My land is nothing like flat and I have my 3033R in 4 wheel drive always. It never sees pavement. Does this have the potential of damaging my machine? Thanks

I only engage MFWD in a tractor that has it when the tractor is slipping with MFWD disengaged and the differential lock engaged. I usually leave MFWD engaged in that situation until I finish the job where the slipping occurred and then disengage it. The main reason I disengage MFWD when it isn't needed is that the front axle is trying to outrun the rear axle by a little bit and there is no way to relieve the resultant driveline binding other than (front) wheel slip. That is harmless in low-traction situations, wears front tires more quickly in situations where there is some traction, and destroys the driveline in high-traction situations like on dry pavement. Turning radius also widens a lot with MFWD engaged too.

Note that some newer tractors will automatically engage MFWD in certain situations, such as when braking to slow down the entire driveline, and disengage it when turning or when traveling above a certain speed, so I am talking about the situations where the operator can actually control whether or not MFWD engages or not.

I believe that the terms FWA and 4wd are used interchangeably but your tractor is 4wd. I've read on this site that the front drive leads the rear by a certain percentage which makes it even more important to use 4wd only on low traction surfaces.

FWA and MFWD are used interchangeably as mechanical front wheel drive is a type of front wheel assist (the other is HFWD, hydraulic front wheel assist, seen on a very small number of older tractors like 4020s.) 4WD on a tractor is much different as it is only on the center-articulated tractors with equal-sized front and rear wheels. The front axle in a 4WD tractor is designed to provide a significant amount of the pulling force on a 4WD tractor rather than merely "assist" the rear axle, and the weight splits between front and rear axles on an MFWD vs. a 4WD tractor show that as they are basically reversed.

I disagree on this. Your truck has the same size tires all around, and if it's 4x4 the manual will say you shouldn't run in 4x4 on hard surfaces either. Does that make it not a "real" 4x4 truck? No, of course not.

Now if said truck is AWD that's a different story.
Anything that is 4x4 and can run all day in it on any terrain generally uses the term "all wheel drive" and such a system will allow for differences in front vs. rear ratios by utilizing a differential between the 2 axles to allow for slip.

As for that term "assist" or "front wheel assist", I read that the name came from a conversion kit offered in the 1950's (?) to add front wheel drive to a 2wd tractor. Apparently some of these kits simply drove the front axle at some random speed with no attempt to match the rear axle speed whatsoever, hence the term front wheel assist.

Four wheel drive automobiles usually are a much different ball of wax entirely than a tractor. A traditional part-time 4WD on a truck does act like a 4WD tractor, you have similar axle ratios front and rear and the front and rear axles are yoked together so you can't turn on any high-traction surface with it engaged. Any sort of full-time 4WD (often called "AWD") is going to have some way to have the front and rear axles not mechanically locked together, whether that's a clutch pack or viscous coupling between the front and rear axles or in the case of battery-powered vehicles, the front and rear axles have completely independent drive motors and no mechanical connection between the front and rear axles at all. There is nothing like a tractor MFWD setup on typical road vehicles with significantly different axle ratios and significantly different tire sizes front and rear.

The tractors I've used that have had MFWD have all had open front differentials. If the front differential locked, you would only be able to go perfectly straight ahead with it locked. All of the 4WD vehicles I've driven have had open front differentials as well. I have only seen locking front diffs on rock crawlers and such.

I think I will discover that there are times when MFWD is not called for. Thanks again for helping me understand this.

I have found that I only use MFWD maybe once every several years in a tractor that has ag tires, sufficient ballast, and isn't trying to pull an implement that is really too big for the tractor. That is true even in hilly and wet areas. Nearly always if I have to engage MFWD ion a tractor it's because one of those three things isn't true.

 

I only engage MFWD in a tractor that has it when the tractor is slipping with MFWD disengaged and the differential lock engaged. I usually leave MFWD engaged in that situation until I finish the job where the slipping occurred and then disengage it. The main reason I disengage MFWD when it isn't needed is that the front axle is trying to outrun the rear axle by a little bit and there is no way to relieve the resultant driveline binding other than (front) wheel slip. That is harmless in low-traction situations, wears front tires more quickly in situations where there is some traction, and destroys the driveline in high-traction situations like on dry pavement. Turning radius also widens a lot with MFWD engaged too.

Note that some newer tractors will automatically engage MFWD in certain situations, such as when braking to slow down the entire driveline, and disengage it when turning or when traveling above a certain speed, so I am talking about the situations where the operator can actually control whether or not MFWD engages or not.



FWA and MFWD are used interchangeably as mechanical front wheel drive is a type of front wheel assist (the other is HFWD, hydraulic front wheel assist, seen on a very small number of older tractors like 4020s.) 4WD on a tractor is much different as it is only on the center-articulated tractors with equal-sized front and rear wheels. The front axle in a 4WD tractor is designed to provide a significant amount of the pulling force on a 4WD tractor rather than merely "assist" the rear axle, and the weight splits between front and rear axles on an MFWD vs. a 4WD tractor show that as they are basically reversed.



Four wheel drive automobiles usually are a much different ball of wax entirely than a tractor. A traditional part-time 4WD on a truck does act like a 4WD tractor, you have similar axle ratios front and rear and the front and rear axles are yoked together so you can't turn on any high-traction surface with it engaged. Any sort of full-time 4WD (often called "AWD") is going to have some way to have the front and rear axles not mechanically locked together, whether that's a clutch pack or viscous coupling between the front and rear axles or in the case of battery-powered vehicles, the front and rear axles have completely independent drive motors and no mechanical connection between the front and rear axles at all. There is nothing like a tractor MFWD setup on typical road vehicles with significantly different axle ratios and significantly different tire sizes front and rear.

The tractors I've used that have had MFWD have all had open front differentials. If the front differential locked, you would only be able to go perfectly straight ahead with it locked. All of the 4WD vehicles I've driven have had open front differentials as well. I have only seen locking front diffs on rock crawlers and such.



I have found that I only use MFWD maybe once every several years in a tractor that has ag tires, sufficient ballast, and isn't trying to pull an implement that is really too big for the tractor. That is true even in hilly and wet areas. Nearly always if I have to engage MFWD ion a tractor it's because one of those three things isn't true.

I don't see how our tractors aren't 4wd when the front axle is engaged (I'm not talking about actual wheels driven because open differentials, ect). Explain to me how they are front wheel assist instead of 4wd. Weight differences between the axles doesn't make any difference in this case and neither does tire size imo because the gearing makes up for tire size differences.