[Akovia]

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.

I think I’ve been assuming that the steep character of my property, lack of hard surfaces, and western Oregon wet ground meant 4x4 was always called for. I have never noticed any kind of binding or resistance on the front wheels, even during sharp turns with an empty bucket. Unlike the old Tundra that bucks like a bronc if I forget to take it out of 4WD and decide to turn the steering wheel. I’ve got some brush cutting to do soon and I experiment with getting in and out of exciting places in 2WD. Thanks for all the comments guys.☮

 

[Treefarmer]

I think I’ve been assuming that the steep character of my property, lack of hard surfaces, and western Oregon wet ground meant 4x4 was always called for. I have never noticed any kind of binding or resistance on the front wheels, even during sharp turns with an empty bucket. Unlike the old Tundra that bucks like a bronc if I forget to take it out of 4WD and decide to turn the steering wheel. I’ve got some brush cutting to do soon and I experiment with getting in and out of exciting places in 2WD. Thanks for all the comments guys.☮

You may find the tractor is reluctant to move out of 4wd after making sharp turns. If so, drive straight for a few feet and/or in reverse for a small distance to unload the tension on the drive train.

 

[coaltrain]

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!

I have some pretty steep slopes that I mow which dictate going only straight up and down. I use 4WD of course to get up without spinning and also on the way down so the tractor doesn’t take off on me.

But at the turns - especially at the bottom going down, I take it out of 4WD to make that turn. I don’t want all the pressure from the weight of the tractor on the one front lower tire when I’m 4WD. It only takes a flick of the lever - pretty easy.

 

[Vern3039r]

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.

 

[dixie460]

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.

 

[arlen]

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:



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.

Edit…I had it backwards originally. Thank you @Vern3039r

Even if everything is brand new and tires are all properly sized as per the engineering, they are designed for the fronts to overdrive the rears. This gives better traction because they are always pulling the rear tread into the dirt/snow for a better bite since most of the tractive force in in the rear.

 

[Vern3039r]

@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%.

 

[arlen]

@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%.
View attachment 911896

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!

 

[RLTherio]

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!

Pre-coffee?

 

[machineryman]

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.

 

[Akovia]

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?🤪

 

[Vern3039r]

@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.

 

[Akovia]

@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.

 

[Mike21]

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.

 

[Treefarmer]

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.

 

[MarkEagleUSA]

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!

 

[dixie460]

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 😂

 

[MarkEagleUSA]

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 😂

Yeah, I guess that's what I meant. 60% of the power goes to the fronts. Just like MFWD, it's designed so the front wheels pull the car and the rears provide traction.

 

[Mike21]

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!

I know when crossing a ditch, if one front wheel is off the ground it is usually spinning. Touching the lock will pull right across it. It takes a few feet to revert back to differential mode. While it is not good to spin it around on hard ground, I don’t think it would damage the machine to leave it in 4WD on soft ground. Our green machines are pretty durable.

Subarus are great little cars but I don’t think you would be turning full lock at 65mph. Unless maybe it was a WRX. 🤔

 

[MarkEagleUSA]

I know when crossing a ditch, if one front wheel is off the ground it is usually spinning. Touching the lock will pull right across it. It takes a few feet to revert back to differential mode. While it is not good to spin it around on hard ground, I don’t think it would damage the machine to leave it in 4WD on soft ground. Our green machines are pretty durable.

Subarus are great little cars but I don’t think you would be turning full lock at 65mph. Unless maybe it was a WRX. 🤔

The front wheel off the ground spins due to the open diff in the axle. Both front and rear, the tire with the least resistance/traction gets the power. Using the diff lock only locks the rear so the front wheel in the air will still spin.

Lots of ag tire retailers have lead/lag calculators. MFWD want 2% to 5% more "lead" in the front and NEVER wants "lag".

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