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a Lawn tractor with Diff/lock

Posted by sergeant 5aIL (My Page) on
Wed, Feb 6, 08 at 13:37

Just saw this on the husqvarna web site.I'm supprised they put Diff/lock on a Lawn tractor and Not there Garden Tractors as well

Here is a link that might be useful: Husqvarna Diff/Lock


Follow-Up Postings:

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RE: a Lawn tractor with Diff/lock

I think the Simplicity Broadmoor has that also?Not really a true differitial lock but I wonder if the Husqvarna is either?


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RE: a Lawn tractor with Diff/lock

The broadmoor has Automatic Controled Traction I would like to see it that Diff/lock on the husqvarna is the same as the broodmoor.


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RE: a Lawn tractor with Diff/lock

I won't be suckered by this type of marketing any more.
Back in my college days I had a 340 duster with a posi rear and a 4-speed that could drive through any snow and not get stuck. I now have a JD 420 with a differential lock that is excellent when you need it. I also have had cars with a "limited slip" rear ends. It sucks it doesn't work it is marketing hype.


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RE: a Lawn tractor with Diff/lock

Since early in 2007 Husq./Craftsman has used Tuff-Torq trannies. Tuff-Torq lists an Auto Diff. Lock as an option in both the K46 and the K57. This is exactly the same as Simplicity's Auto Controlled Traction.

What it says to me is that Husq., who has always made Box Store Babies, may be trying to move into the premium lawn tractor market. This tractor looks like it is being positioned to compete in the Regent/Broadmoor/X-300 market. Perhaps they think they can fill the position left by the exit of Toro/Wheelhorse.

It does seem that since Electrolux has spun off Husqvarna that Husq. has tried to improve their products. First they eliminated those hokey auto-drive, cvt transmissions. Now all autos at Sears/Husq are K46s or K66s, although this new tractor may have a K57, I can't tell from that spec sheet. And they seem to have improved their engines too, this tractor has a Vanguard, and Kawasaki's are available on some models.

It's good to see a traditional mass market retailer trying to move up the food chain. Whether they suceed or not remains to be seen.


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RE: a Lawn tractor with Diff/lock

I have a simplicity conquest with diff lock. It's the most useful feature on the thing. I never get stuck pulling the aerator up hills anymore. Great feature. Good luck.


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RE: a Lawn tractor with Diff/lock

Positraction (posi) is the same as a limited slip differential.

If you liked the one in your duster, why wouldn't you like the others? They are the same, just named differently.


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RE: a Lawn tractor with Diff/lock

There are half a dozen different 'limited slip' differentials, some good and some not so good . . . . GM's "Positraction" (a clutch-type) is just one of them

The geared Torsen (TORque SENsing) is the best of the lot, IMO

Don


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RE: a Lawn tractor with Diff/lock

"Posi rear" in my experience is always on. Always turning both wheels at the same speed. They are locked together.
The manufactures name them differently because they are playing a marketing game. To get you to believe they are the same! Most are limited slip. Most are not worth having in my experience.


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RE: a Lawn tractor with Diff/lock

Posi, LSD, Auburn are all the same, they are a clutch type diff, and like the clutch in your car they can wear out. Also when you change the oil in the diff there us usually an additive that you should use to help the clutch pack last longer. True "locking" diffs are usually reserved for extreme apps. Rock crawling, Drag racing, Mud Racing, real tractors....those kind of things. It is real easy to tell if a diff is a true "locked" rear....just try to push it around a corner. To do it right most people use an air locker, push a button and the diff is locked, If you want to do it on the cheap Weld the diff, but you better know what you are doing.

My JD650 had a mechanical lock and it has come in handy from time to time. It just locks the back wheels not the fronts.


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RE: a Lawn tractor with Diff/lock

I step on a lever to engage my diff lock on my cub gt3235. Gives me the traction I need when I need it with out destroying my yard. Parts of my yard are always damp and the locking diff works great in those areas.

Posi rears are definitely worth it for street cars. Yes your average little honda doesn't need it, but when the hp starts going up, its pretty much necessary. I couldn't image driving my 69 camaro without it especially behind a 425hp smallblock.


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RE: a Lawn tractor with Diff/lock

The ole peg leg, one wheel peel......


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RE: a Lawn tractor with Diff/lock

Tractors that have an "operator controlled" differential lock-up feature (pedal engaged or servo engaged) ARE NOT "positive traction" or "limited slip differentials". A positrac or limited slip differential requires no action from the operator for activation, and all the "positrac" action is from the center or core differential components. Where there is a foot pedal or servo engaged lock-up feature, you actually have a sliding gear or "clutch" that is shifted into mesh with a mating gear surface and when the 2 gears are in mesh, the "differential gears" are defeated or "over ruled" and the characteristic "power flow to wheel with LEAST TRACTION" is overcome, forcing the power to flow evenly to BOTH wheels.


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RE: a Lawn tractor with Diff/lock

Posi's or LSD prevent wheel slip before it starts. They have disc clutch packs which are under preloaded by a spring assembly. These spring assemblies are located behind each differential gear. When torque input increases the clamping load on the clutch packs increases. So apply more power, the more it clamps. In order for the clutch packs to work, you need to add a fricton modifier to your geal oil.

Lockers work a little different. The Detroit Locker delivers 100% of the torque to both drive wheels. It basically keeps both wheels engaged, but it has the ability to automatically unlock and allow wheel speed differentiation when required.

Call it whatever you want on a tractor. Whether you step on a pedal or not the principal is the same, to apply power to both wheels.


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RE: a Lawn tractor with Diff/lock

Ditto to what mownie said. Best explanation there has been on this thread.


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RE: a Lawn tractor with Diff/lock

Excellent descriptions of the diff lock. One problem for me. I have a Simp Conquest w/ diff lock. Don't know how to work the darn thing. It doesn't always seem to depress for me. Also, if anyone knows, once you do depress it, does it stay down, or do you have to keep your foot on it?? Thanks


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RE: a Lawn tractor with Diff/lock

mckeon110,

To engage the Diff lock on the Simp, simply push down with your left foot. It might not engage right away, put as you apply the hydro either forward or revers it will drop in and engage the diff lock. You can keep it locked for a short time as long as long as their is pressure to keep the wheel locked( ie your foot on the hydro). Once you let up it will disengage on its own. The best bet to keep it locked is to simply hold the lever down with your left foot when you need the differential locked.


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RE: a Lawn tractor with Diff/lock

Thank you, the thing was driving me crazy. It still seems to be a little tough engaging though.


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RE: a Lawn tractor with Diff/lock

One more little detail about differential locks: When you step on the pedal to engage the lockup, unless the 2 mating gears are "aligned to mesh" at that very moment, the gears will just push against each other without actually merging into the locked position. This is because the left and right wheels have enough traction to keep from slipping and so the teeth on the 2 gears also continue to turn in synchronized fashion without rotating their teeth to a mating point. This is noticed by the operator as " a high, hard pedal" (the engaging pedal for diff lock). This is most likely to occur if the operator "anticipates" wheel slippage (believes that the extra traction will be needed) and tries to engage the diff lock BEFORE wheel slip actually happens. There is nothing wrong with pre-selecting to engage diff lock ahead of the actual loss of traction event, but if you don't "feel" the engagement take place (feel the pedal drop all the way down) you should try to "help" the gears to align by slightly (very slightly) turning the STEERING WHEEL in one direction and then in the opposite direction. This forces the 2 gears of the diff lock to rotate just a little in an "unsynchronous fashion" which will allow their teeth to match and merge together. Now, to the opposite side of the coin. Sometimes the diff lock will remain "locked" after the need for extra traction is gone. This is due to "drive line wind-up", "elastic loading", or "torsion" (different names, same phenomenon) of the drive line components between the differential unit and the ground surface the tractor is rolling on. This "elastic loading" occurs mainly in the tires and keeps just enough "grip" on the teeth of the 2 lock-up gears to prevent them from disengaging or moving out of mesh. This occurs most often if there is a need to make a turn while the diff lock is engaged. (An illustration of elastic loading is the rubber band that was used to power the little balsa wood toy airplanes of my youth. The rubber band was attached to the propeller shaft on one end and anchored to the fuselage on the other end. You would "wind up" the rubber band to store energy in it. When the rubber band was wound up tight, you could feel it in the form of pressure or resistance on the finger you were using to wind the propeller. This pressure is "elastic loading" and is analogous to what happens in between the 2 tires on your tractor when the diff lock is engaged in turns.) To help the diff lock "turn loose" or "let go" when it is no longer needed, just do the steering wheel trick same as for engaging. You will not "hurt" or damage anything in the drivetrain by the diff lock remaining engaged (unless you are running on paved surfaces for a prolonged time) but you WILL notice that your ability to get the tractor to steer will be affected until the diff lock disengages. I want to add that the "steering wheel trick" only works if the tractor is in motion and rolling. There is no "magical linkage" between the steering wheel and the diff lock. :^)


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RE: a Lawn tractor with Diff/lock

Man, are you a scientist??? Thank you, and you must be an english lit teacher because your expanation made perfect sense. Maybe I should ask you why my brand new 23hp briggs vanguard, is surging-hunting, mostly when blades are engaged. The dealer took it back and put a carb kit in it. The thing is still not right!! any thoughts. I no nothing about engines, just bought the best tracor i could afford. Thanks again. Kevin


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