It's my grandpa's tractor. I've been running it a little while. Currently 650 hours and he got it at around 500-550. I never had an owners manual though. I've not much experience with tractor maintenance either I guess. Just greasing all the fittings I could find and topping off whatever fluids I could find if needed. Didn't know much about 4wd or HST. Noticed the front left wheel has lost all power and decided it was time to print off a manual. That's how I discovered it's supposed to have oil in the front axle, which it turns out was dry when i checked. Got it refilled but it's still definitely only a 3wd. Might even be more like 2 and a half. Front right has power but not sure how much. Front left is 100% a dud. Only way it'll spin on it's own is if you lift it off the ground otherwise its free wheeling. Was wondering before i tear into it if anyone knows what kind of parts I should expect to be all chewed up in there. Are there things in the axles that commonly tear up when the fluids are neglected? Im assuming the spindle is probably toast.
B2710 4wd has become 3wd
- Thread starter Ethan P Dobbins
- Start date
ken erickson
Well-known member
Equipment
B7100 hst, 2650 front mount snowblower, L2501 hst qa loader
Your tractor has a front “open differential”. Back differential should have an operator engaged differential lock. In Reality, depending on traction conditions, at best you have 3 wheel drive with rear differential locked. An open differential sends power to the wheel/tire with the least traction.
After thinking about it, its simplistic for me to say that an open differential sends power to the wheel/tire with the least traction. An open differential supplies torque equally to both but that torque is limited to the wheel with the least traction. If one wheel is on glare ice that wheel will spin, which takes very little torque , and the differential will send that same amount of torque to the tire with traction. But due to such little torque that wheel does not turn to propel the vehicle.
After thinking about it, its simplistic for me to say that an open differential sends power to the wheel/tire with the least traction. An open differential supplies torque equally to both but that torque is limited to the wheel with the least traction. If one wheel is on glare ice that wheel will spin, which takes very little torque , and the differential will send that same amount of torque to the tire with traction. But due to such little torque that wheel does not turn to propel the vehicle.
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So, with an open differential whichever side is putting up less resistance will spin.
For example, if you jacked up all 4 wheels of the tractor and put it in 4wd and in gear and just let all 4 wheels spin, you COULD actually stop one of the front wheels with just your hands, and all that would happen is the other front wheel would start spinning faster.
So unless you actually immobilize the other front wheel itll be hard to tellf if the wheel youre talking about can actually transfer a lot of torque or not.
For example, if you jacked up all 4 wheels of the tractor and put it in 4wd and in gear and just let all 4 wheels spin, you COULD actually stop one of the front wheels with just your hands, and all that would happen is the other front wheel would start spinning faster.
So unless you actually immobilize the other front wheel itll be hard to tellf if the wheel youre talking about can actually transfer a lot of torque or not.
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Put it in 4WD and drive out to a grassy area Put the loader bucket up against a big tree, point the wheels straight forward, rev the engine and try to push the tree over. Bet both front-wheels spin on the grass.
Dan
Unless there is a mechanical reason for it (front axle/diff damaged) an open differential is free to 'bias' to either side (left or right axle shaft). Under ideal conditions it is even possible for both front axle shafts to receive even amounts of power (but not likely). Hence, you have 3 wheel drive (with rear diff locked).
It is somewhat a misnomer that a 4wd tractor is truly 4 wheel drive as the label suggests. What is actually meant is that ANY of four wheels is 'capable' of being driven.
A 4WD tractor when in 2wd (and open rear diff) is actually ONE wheel drive (owing to power bias) until the differential is mechanically locked (providing even power to both rear tires).
When in 4wd depending on conditions....you might see just one front tire receiving power (possibly even spinning some) or it might switch briefly from one side to the other. But in any case....without the benefit of mechanical 'locker' in the front....you essentially have 3wd.
It is somewhat a misnomer that a 4wd tractor is truly 4 wheel drive as the label suggests. What is actually meant is that ANY of four wheels is 'capable' of being driven.
A 4WD tractor when in 2wd (and open rear diff) is actually ONE wheel drive (owing to power bias) until the differential is mechanically locked (providing even power to both rear tires).
When in 4wd depending on conditions....you might see just one front tire receiving power (possibly even spinning some) or it might switch briefly from one side to the other. But in any case....without the benefit of mechanical 'locker' in the front....you essentially have 3wd.
I took it out and did exactly this on the grass right after the dew fell and you're right. I was able to get both sides to spin depending on which side of the loader bucket was pressing on the tree. I guess i must just be the way i drive it. Always seems like it's the left side binding up but I'm doing a lot of scooping creek gravel which is pretty slick work.
Thanks folks. Makes a lot of sense. I took it out and went up against a big tree with the loader like someone said and sure enough both wheels will spin just fine. Depending on which side of the bucket was pressing the tree one side would spin while the other doesn't. Didn't know all that about the 4wd biasing to one side or the other but it makes sense now. I do appreciate it. I was fearing i was gonna need to tear into it and replace a bunch of stuff 
. I guess it must just be the way I've been running it that made something seem wrong to me. Seems like the left is the one that always binds while the right one spins but I'm doing the same thing over & over in the same locations scooping creek gravel & manure and whatnot so that would explain it.
. I guess it must just be the way I've been running it that made something seem wrong to me. Seems like the left is the one that always binds while the right one spins but I'm doing the same thing over & over in the same locations scooping creek gravel & manure and whatnot so that would explain it.Good idea. It's about half 10w30 anyways because i ran out of transmission/hydraulic fluid halfway through filling. Wanted to get something in there at least. I'll run it a little while to let it churn up and degunk itself and then drain it sometime when I get some more oil.
All it takes to make one wheel consistently spin is a slight incline, which you are almost surely encountering if you're talking about a creekbed.
Im a FIRM believer that 'any oil is better than no oil' in most low-speed applications. I've even heard of people replacing the oil in gearboxes entirely with 'cornhead grease'. I agree with your plan to just let it circulate picking up junk and then do another drain and fill.
Im a FIRM believer that 'any oil is better than no oil' in most low-speed applications. I've even heard of people replacing the oil in gearboxes entirely with 'cornhead grease'. I agree with your plan to just let it circulate picking up junk and then do another drain and fill.
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Open differentials are interesting mechanisms. I have plowed snow with my B7200DT for a couple decades now and when temps are right around feezing it's fairly common that I lose traction going up a very slick paved surface and basically sit there dead in the water, not moving, with ALL 4 wheels digging away. That usually deteriorates pretty quickly into a backwards spinning out of control slide.
Dan
As stated, in an open diff, the wheel with the least resistance with get most of the power. When I say most of the power, it's based on the weight of the vehicle on each wheel and traction with the ground. If the vehicle is completely off of the ground, jack up on all four wheels, you could stop a tire carefully, with your bare hands.
Many of the AWD vehicles today, also have a center diff. Which is a differential between the front and rear axles. (Generally tractors don't). So, in reality, an AWD car can fail you with only one wheel spinning. AWD is 1 wheel drive. Most of those have a power transfer option eliminating the center diff, or a wheel brake setup to brake the wheel or wheels with less traction. Electronic adjustment makes some of these Subaru's and the like, so very capable.
Many of the AWD vehicles today, also have a center diff. Which is a differential between the front and rear axles. (Generally tractors don't). So, in reality, an AWD car can fail you with only one wheel spinning. AWD is 1 wheel drive. Most of those have a power transfer option eliminating the center diff, or a wheel brake setup to brake the wheel or wheels with less traction. Electronic adjustment makes some of these Subaru's and the like, so very capable.
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
On my AWD cars:
The center "differential" is actually a computer controlled torque dividing viscous coupling that controls the distribution of engine torque front to rear. In normal driving its 60:40 rear drive. It's never zero in either direction and there is always some power going to both axles.
The front and rear axles have open differentials and the computer controlled brake system is used to sense and individually limit slip on any wheel. Just like steering brakes on an old tractor but a whole lot faster and far more effective.
The stability cintrol ECU is the command center that coordinates and synchronizes that orchestra.
In normal operation it's silky smooth but in low speed chsllenging conditions like deep snow and performance tires it can get a bit rough.
Dan
Exactly. A viscuos coupling is a computer and / or pneumatic (oil based) clutch.
Computers make life easier. Sometimes.
I prefer no center differential, and manual or electric actuated diff lockers.
But by wife just wants to get where she's going. Therefore electronic AWD is best for the non-mechanical.
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