ahoude
Member
I should have mentioned that my property is primarily flat with no steep hills. A few wet spots but the tractor bairly misses a beat going through them.
4x4 Question
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Soundguy
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N80 said:
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.. i just think running it in 4wd, when not needed, adds wear that is not needed... I don't drive my truck in 4wd just because I pull off the pavement, unless I think I'm gonna get stuck, or need to pull something.
Soundguy
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patrick_g said:
What about Nh sensitrack?
patrick_g said:
That's a big difference there...50%.. and is so general as to be almost useless. You have to take other factors into comparison.. like weight and size. Also.. hp? drawbar hp? pto hp? engine hp? again.. to vauge... No reason why you would be able to run a 4x4 tractor with 50% less hp and get the same work down on a stationary power setup.. like a sawmill or genny...
Or pulling a big mower.. Or a hay baler... While some tractors may have the hp.. you still need the weight to be safe.
I think it is more accurate to say that a 4x4 can perform some of the drawbar tasks that would require a larger 4x2 tractor, simple due to traction .. not specifically hp.
Soundguy
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ahoude said:
I think many people here are confusing 'hurt' with 'wear'. I'm advocating that using 4wd under a laod adds wear to the system.. I did not say it hurt it. ( vs using 2wd ).
Obviously as has been pointed out manny times. if 4wd is needed.. by all menas.. use it. If your land changes so much that you can use 4wd and would have to be shifting in and out.. I'd agree... just leave it in 4wd, save for the high traction areas.
Soundguy
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In spite of what happened.. I think he still should have taken it out of 4wd at the blacktop..... though obviously not before.. especially considering the teraine he was crossing to get to the blacktop. His method sounds more like an airplane pilot turning off his engine as he is coming in for a landing.. so that he doesn't forget to turn it off after he lands... Unfortunately.. the engine would be a real help while landing..e tc..
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dirtworksequip said:
ovrszd
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Okay, let's try for some clarity in the discussion about the strength of the front drive setup versus the rear drive setup. I have a parts manual that I downloaded for my B2910. So I'll try to describe the drivetrain for each end of the tractor based on that manual.
First the rear. A straight shaft enters the rear axle case and has a pinion gear attached to the end which drives a ring gear that is fastened to the carrier containing the spider gears (which allow the two axles to spin at different speeds). The spider gears are directly fastened to the axle shafts using splines. Very few spots for wear and an expected life span in the thousands of hours easily. Very rare to see someone have to rebuild any of this driveline with the exception of maybe the spider gears under severe abuse of the rear locker. This driveline takes stress every time the tractor is moved, regardless of whether we are in 4x4 or 2x4. Do we all agree to this???
Second the front. In the bottom of the rear axle assembly is an additional gearbox bolted on that has a sliding gear that engages and disengages the 4x4 when you move the lever thru a counter shaft and gear assembly coming off the pinion shaft described above. This in turn drives a forward shaft that goes into a ujoint, then a mid shaft transfers the power forward to another ujoint, then another mid shaft transfers the power forward to a shaft coupler, the coupler is fastened to the pinion gear in the front axle assembly. That pinion drives a ring gear that is fastened to the carrier containing spider gears (which allow the two axle shafts to spin at different speeds). The spider gears are directly fastened to the axle shafts using splines. These axle shafts extend outward into the front wheel spindles where there is another angle gear which drives against an opposing angle gear that is fastened to a vertical shaft to transfer the power downward thru a shaft on each side into another pinion gear. That pinion gear drives another ring gear that is fastened to a carrier that transfers that power into a horizontal shaft which is fastened to the front wheel assembly. So this system contains 3 ring gear/pinion setups, 4 angle gears, 1 set of spider gears, 1 shaft coupler, 2 ujoints, 3 straight cut gears, 1 sliding gear and 9 splined shafts. Do we all agree to this??
Can we agree that the complexity and thus the lifespan of these two drive systems is considerably different?? Can we agree that if used under equal conditions and stresses and number of hours that the front drive system could be expected to fail earlier than the rear drive system simply because of complexity?? If you cannot find it in yourself to agree to this then simply stop reading and ignore anything else I have to say about this subject, that's your privilege.
If you agree with my explanation, description, and final analysis about the above drive system, then wouldn't you also agree that you should minimize the amount of stress being put on the front drive system?? If you agree wouldn't you also agree that you should use your 4x4 when you need it and disengage it when you don't?? That's why they put that lever there, to use.
Now in regards to N80's (Hope I remembered his name right) comments about his L4400 not getting "bound up" when he turns in 4x4. As I said way back a few posts ago, some tractors have traction sensitive setups and will not bind. I'm not personally familiar with an L4400 so maybe it has this system. It uses a complex speed sensitive system that locks and unlocks the 4x4 system based on need. When you make a tight turn such as at the end of a field, the tractor's system recognizes that difference in wheel speed and allows the 4x4 system to unlock for the turn. If you put the tractor in a situation where the wheel speed variance between front and back exceeds what you encountered in a turn, it locks and offers 4x4 drive. This type of 4x4 system is very common in SUVs on the road today. Most offer some sort of "full-time" 4x4 using a method similar to this. They usually use the Anti Lock Brake sensors to activate and deactivate this system.
In regards to taking more HP in 4x4. If you believe my above statements then you must also agree that it would take more HP to drive all of the above described systems versus just the simple rear drive system. Again, that's just simple physics. I refer back to example of getting "bound up" and how much force it takes to move the tractor in that condition. If you have a traction sensitive 4x4 system this may not apply to you. Your burden is that when you are driving around with this system engaged you are wearing out the parts that are constantly engaging and disengaging without any input from you.
Bottom line, use it when you need it, disengage it when you don't. Your tractor will thank you!!!
First the rear. A straight shaft enters the rear axle case and has a pinion gear attached to the end which drives a ring gear that is fastened to the carrier containing the spider gears (which allow the two axles to spin at different speeds). The spider gears are directly fastened to the axle shafts using splines. Very few spots for wear and an expected life span in the thousands of hours easily. Very rare to see someone have to rebuild any of this driveline with the exception of maybe the spider gears under severe abuse of the rear locker. This driveline takes stress every time the tractor is moved, regardless of whether we are in 4x4 or 2x4. Do we all agree to this???
Second the front. In the bottom of the rear axle assembly is an additional gearbox bolted on that has a sliding gear that engages and disengages the 4x4 when you move the lever thru a counter shaft and gear assembly coming off the pinion shaft described above. This in turn drives a forward shaft that goes into a ujoint, then a mid shaft transfers the power forward to another ujoint, then another mid shaft transfers the power forward to a shaft coupler, the coupler is fastened to the pinion gear in the front axle assembly. That pinion drives a ring gear that is fastened to the carrier containing spider gears (which allow the two axle shafts to spin at different speeds). The spider gears are directly fastened to the axle shafts using splines. These axle shafts extend outward into the front wheel spindles where there is another angle gear which drives against an opposing angle gear that is fastened to a vertical shaft to transfer the power downward thru a shaft on each side into another pinion gear. That pinion gear drives another ring gear that is fastened to a carrier that transfers that power into a horizontal shaft which is fastened to the front wheel assembly. So this system contains 3 ring gear/pinion setups, 4 angle gears, 1 set of spider gears, 1 shaft coupler, 2 ujoints, 3 straight cut gears, 1 sliding gear and 9 splined shafts. Do we all agree to this??
Can we agree that the complexity and thus the lifespan of these two drive systems is considerably different?? Can we agree that if used under equal conditions and stresses and number of hours that the front drive system could be expected to fail earlier than the rear drive system simply because of complexity?? If you cannot find it in yourself to agree to this then simply stop reading and ignore anything else I have to say about this subject, that's your privilege.
If you agree with my explanation, description, and final analysis about the above drive system, then wouldn't you also agree that you should minimize the amount of stress being put on the front drive system?? If you agree wouldn't you also agree that you should use your 4x4 when you need it and disengage it when you don't?? That's why they put that lever there, to use.
Now in regards to N80's (Hope I remembered his name right) comments about his L4400 not getting "bound up" when he turns in 4x4. As I said way back a few posts ago, some tractors have traction sensitive setups and will not bind. I'm not personally familiar with an L4400 so maybe it has this system. It uses a complex speed sensitive system that locks and unlocks the 4x4 system based on need. When you make a tight turn such as at the end of a field, the tractor's system recognizes that difference in wheel speed and allows the 4x4 system to unlock for the turn. If you put the tractor in a situation where the wheel speed variance between front and back exceeds what you encountered in a turn, it locks and offers 4x4 drive. This type of 4x4 system is very common in SUVs on the road today. Most offer some sort of "full-time" 4x4 using a method similar to this. They usually use the Anti Lock Brake sensors to activate and deactivate this system.
In regards to taking more HP in 4x4. If you believe my above statements then you must also agree that it would take more HP to drive all of the above described systems versus just the simple rear drive system. Again, that's just simple physics. I refer back to example of getting "bound up" and how much force it takes to move the tractor in that condition. If you have a traction sensitive 4x4 system this may not apply to you. Your burden is that when you are driving around with this system engaged you are wearing out the parts that are constantly engaging and disengaging without any input from you.
Bottom line, use it when you need it, disengage it when you don't. Your tractor will thank you!!!
neverenough
Silver Member
How about I inject some facts into the thread, sort of kicking the bee hive.
Fact: Buy a tractor from a company who knows tractors, like John Deere, and they will tell you, right in the "operating the tractor" section of the owners manual, to only use the MFWD when needed for added traction and braking. The proper way to use MFWD. For all the newbies, MFWD stands for Mechanical Front Wheel Drive. Technically, unless the front and rear wheels are the same size, like on a truck, or large ag tractor, it's not 4X4 or 4 wheel drive (6 times a year).
Fact: The MFWD system is designed to give added traction in sub standard conditions. Using MFWD in on high traction surfaces, including dry lawns and packed gravel and dirt, WILL result in added driveline stress, and premature failure. Chances are, this failure will occur when you are decending a steep hill with a heavy load, or stuck up to the axles in heavy mud becouse you went into the mud with the MFWD locked in, and kept going, hoping it would also get you out. My 4 wheel drive ag tractor has pulled out MFWD tractors almost as many times as it has gone out to the field to disc.
Fact: Using a MFWD tractor to do more work than the tractor was meant to do, just becouse it has MFWD, will cause serious saftey issues and premature wear on the tractor.
Fact: The most important part of a tractor is an operator who knows how to operate the tractor, and when to use each of the features on the tractor.
Fire away boy's and girl's....
Fact: Buy a tractor from a company who knows tractors, like John Deere, and they will tell you, right in the "operating the tractor" section of the owners manual, to only use the MFWD when needed for added traction and braking. The proper way to use MFWD. For all the newbies, MFWD stands for Mechanical Front Wheel Drive. Technically, unless the front and rear wheels are the same size, like on a truck, or large ag tractor, it's not 4X4 or 4 wheel drive (6 times a year).
Fact: The MFWD system is designed to give added traction in sub standard conditions. Using MFWD in on high traction surfaces, including dry lawns and packed gravel and dirt, WILL result in added driveline stress, and premature failure. Chances are, this failure will occur when you are decending a steep hill with a heavy load, or stuck up to the axles in heavy mud becouse you went into the mud with the MFWD locked in, and kept going, hoping it would also get you out. My 4 wheel drive ag tractor has pulled out MFWD tractors almost as many times as it has gone out to the field to disc.
Fact: Using a MFWD tractor to do more work than the tractor was meant to do, just becouse it has MFWD, will cause serious saftey issues and premature wear on the tractor.
Fact: The most important part of a tractor is an operator who knows how to operate the tractor, and when to use each of the features on the tractor.
Fire away boy's and girl's....
ovrszd
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neverenough said:
No rounds fired from this side. You effectively made my case. Also cleared up the technical definition of 4x4 versus MFWD. Thanks for the technical input!!!
Soundguy
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Good posts guys.. nice and lean too.. no fat.
Soundguy
Soundguy
OkieG
Veteran Member
Everyone who intends to use 2WD on pavement, but has forgotten to disengage the 4WD a time or two...raise your hand! I hope mine isn't the only hand raised.
One of the many times I've forgotten resulted in catastrophic front axle damage...Maxing out the loader forks with a partial pallet of bricks I needed to move a half mile on asphalt. At the end of the trip I noticed fluid leaking onto the pavement. The lower spindle shaft bearing had "exploded" and broke a hole in the cast iron spindle housing.
The front axle MFWD drive train on my tractor doesn't look to be built nearly as heavy as the rear drive train. I believe the front axle is relatively delicate compared to the rear and certain "bonehead" situations will make that weakness painfully clear.
My intent, even before the accicent, was to use MFWD whenever needed, but only when needed. ie 2WD unless MFWD is required.
OkieG
One of the many times I've forgotten resulted in catastrophic front axle damage...Maxing out the loader forks with a partial pallet of bricks I needed to move a half mile on asphalt. At the end of the trip I noticed fluid leaking onto the pavement. The lower spindle shaft bearing had "exploded" and broke a hole in the cast iron spindle housing.
The front axle MFWD drive train on my tractor doesn't look to be built nearly as heavy as the rear drive train. I believe the front axle is relatively delicate compared to the rear and certain "bonehead" situations will make that weakness painfully clear.
My intent, even before the accicent, was to use MFWD whenever needed, but only when needed. ie 2WD unless MFWD is required.
OkieG