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Skipper

Thoughts on upgrading 8 pinion diff to LSD or Lock

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I have been mind messing with the idea of upgrading the strong 1 1/8" 8 pinion rear end to LSD or Lock type diff. I think there are a few options, but I am not sure my logic is spot on, so please comment, and let's see if we can come up with a good solution together.

 

First question you might ask is: Why? Well I often find myself in a situation where one wheel slips, and I'm stuck. With both wheels turning I would have been able to go on. But, you then say, then use a 10 pinion rear end. Yes, but that is kind of just not that strong build. In other words, I am not sure it can be trusted to hold up under heavy duty use. That leads me back to the idea of modifying the strong 8 pinion unit.

 

Let's take a quick look at the different types of common diffs:

 

Open diff. This is the standard type where each wheel can rotate at its own speed, regardless of the other wheels speed. Strong suits is optimum steer-ability, and minimal tire wear on hard surfaces. This type is thus very gentle on your lawn. Cons is that traction is limited to that one of the wheels with least traction. When it then starts spinning, the wheel with least traction slips and spins, and power goes from the still holding strong wheel into spinning, and you get stuck / unable to move on.

 

Then there is normal automotive LSD's of different constructions, and they basically do the same thing. They all have a system in place that has a small amount of predefined limited slip, but no more than you can still steer well. When put under load, they lock more and more up, as you increase the power you load it with. Now as I see it, the problems with this type is cost due to its complexity, and its inherent bulkiness. Furthermore I am not sure how much better it will be than the LSD we know from the 10-pinion diff, since the amount of force we can load it with is relatively small, considering the rather low weight and there by traction of our WH tractors. Yes they can be had custom made to suit the needs, but at a price no one would ever pay for it. I think this one will be hard to fit and pay for.

 

And finally we have fully locking diffs. They work by fully locking the wheels speed to be identically. Pros is of cause super good traction, and at the cost of very poor steer-ability when locked up.They come in different types too. The automatic centrifugal locker, that locks up via centrifugal forces. Our wheels do not go fast enough to use this type. Then there is the manual locker, that can be operated via compressed air or direct mechanically. These are rather costly, and it might be troublesome to build that manual function inn. Last option on this shelf, is a very simple, and rather cheap (compared to the others) option. I call it an open locker, it is often called an auto locker, and it comes from many vendors, like this https://www.torqmasters.com/products/category/automatic_locker

Now this might just fit the bill. It simplified allows one wheel to freewheel faster than the other, and at the same time it dos NOT allow the other to go slower.  So basically it should let you turn on the lawn like an open diff, and as soon as one wheel looses traction it locks them together, and releases the lock again automatically as soon as there is no use for it. It seems to be the best compromise as far as I understand it, and it is a tight little package that slips in place instead of the spider gears. I'm thinking this could be adapted. Only situation where I see a problem with this, is in situations where there is a large constant pressure on the rear end. In this situation it will be locked up, and it will be harder to steer. Like for instance when plowing soil etc. I can not get my mind around if it this a deal breaker or not. Do not see why it should be, but.......?

 

It looks like something I might want to give a shot, if it is a good solution.

 

What do you fine people think? :)

 

 

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Posted (edited)

Those torq (lunchbox lockers) are intended for automotive type solid axles, ie what you would find in your truck, a jeep....not too sure they could be adapted to fit a tractor rear end. Just installed one in the front of jeep last year, Dana 30 axle, works great for off road use. As far as your steering with a locked rear axle, not sure it would be affected much at all. You may feel a bit more “push” while turning on hard surfaces, but wouldn’t  be nearly the struggle of a locked front axle on 4x4 turning on pavement 

Edited by classicdmax
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Like classicdmax said it would be hard to adapt it in there but I would definitely do that if I was you, if you try let us know how it comes out 

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i had my 8 pinion rear in my pulling tractor locked for a couple of pulls and the traction was great,but it was a real bear to turn if you did not have much room.i ended up unlocking it.

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18 hours ago, classicdmax said:

Those torq (lunchbox lockers) are intended for automotive type solid axles, ie what you would find in your truck, a jeep....not too sure they could be adapted to fit a tractor rear end. Just installed one in the front of jeep last year, Dana 30 axle, works great for off road use. As far as your steering with a locked rear axle, not sure it would be affected much at all. You may feel a bit more “push” while turning on hard surfaces, but wouldn’t  be nearly the struggle of a locked front axle on 4x4 turning on pavement 

 

Nice insight. This is what I hoped for. Some first hand experience.

 

Can you elaborate on the function, and especially on how well this type of auto locker system works in regards to "unlocking under load and letting one wheel freewheel faster? Is it smooth or jerky, or is it just like driving around like before (doubt that a bit), but please fill in the blanks. The performance of the system when locked is self explanatory, but the transitions from one state to the other, under load and also when just putting along, is what I really would like to hear a lot more about.

 

Thanks :-)

2 hours ago, ricksrj58 said:

i had my 8 pinion rear in my pulling tractor locked for a couple of pulls and the traction was great,but it was a real bear to turn if you did not have much room.i ended up unlocking it.

 

Yes that is a given when it is locked all the time. The idea behind this type of auto lock diff is that it locks and unlocks on the fly. The exercise is to figure out if it does that smooth enough, or if other options should be explored, and if it could be adapted to the WH trans.

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Wheel speed is what engages locker....not sure if these tractors have the wheel speed to actuate the spring mechanism. Although affordable, they are not of the heavy duty nature that a full carrier type lockers are. For off-road use they don’t tend to hold up very long pending how heavy of a foot the driver has. IF they could be adapted to a tractor, I’m sure they’d be just fine 

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1 hour ago, classicdmax said:

Wheel speed is what engages locker....not sure if these tractors have the wheel speed to actuate the spring mechanism. Although affordable, they are not of the heavy duty nature that a full carrier type lockers are. For off-road use they don’t tend to hold up very long pending how heavy of a foot the driver has. IF they could be adapted to a tractor, I’m sure they’d be just fine 

 

Hmm as i understand it, the auto lockers/lunchbox types, lock up from the torque, and not the speed of the rotations. Or am I missing something here?

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1 hour ago, Anglo Traction said:

You may find Mark's (Meadowfield) Thread on his marvelous modification worth a read. I'm sure he won't mind me posting a link for you here-

http://www.wheelhorseforum.com/topic/48814-project-bendy-4x4-gets-a-locking-diff/

Regards

 

Thanks. This is seriously cool, but also out of reach for everyone not being a very skilled machinist with a very well equipped machine shop at disposal. ;-)

 

I'm hoping for a solution that would entail a lot less custom work, albeit it will not be possible without a certain amount of it I'm sure. 

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I wish it were, as I’ve fancy’d The same idea for my 73 no name

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9 minutes ago, classicdmax said:

I wish it were, as I’ve fancy’d The same idea for my 73 no name

 

I think you should look a little into the link to that Aussie locker. It has nothing to do with rotational forces engaging it. I know there are other types of automatic Lockers that use centripetal forces to engage, and they will clearly not work as you also point out. I am however fairly sure this other type will work if it can be adapted, only issue I see is if it disengages smoothly enough, or if all torque should be lifted before it does. If so, I think it's back to the drawing board to see if a progressive preloaded LSD can be adapted, even though they are bulky.

 

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Aussie locker is the same as Torq, and Lokka is another. from what I know it will stay engaged until lack of torque being applied to both wheels. I used Lokka brand in my jeep, here is a much better explanation than what I can offer

http://lokka.com/howitworks

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My snow season horses are all 10 pinion and have survived pushing large amounts of snow.  i liked them so much I put a 10 pinion in my  310-8 that has big ags.  She is used to haul things around again no issues.  My thought is if you are planning on pulling something so extreme you would break the differential you probably should get a bigger tractor.  that would be cheaper (and more reliable) than trying to build some locking system.  The other thing to consider is if you build a stouter locking  differential what is the next weak link in the chain to break...the frame to tranny plate.????

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15 minutes ago, pfrederi said:

My snow season horses are all 10 pinion and have survived pushing large amounts of snow.  i liked them so much I put a 10 pinion in my  310-8 that has big ags.  She is used to haul things around again no issues.  My thought is if you are planning on pulling something so extreme you would break the differential you probably should get a bigger tractor.  that would be cheaper (and more reliable) than trying to build some locking system.  The other thing to consider is if you build a stouter locking  differential what is the next weak link in the chain to break...the frame to tranny plate.????

 

I see what you are getting at, but it is actually not that extreme conditions that calls for an LSD or Lock diff IMO. It is actually more in the slippery situations, and yes, the 10 pinion would probably do just fine there. Problem arises when that tractor is also being used hard, like loader work etc. Then I fear that the 10 pinion unit will not hold up, and that has nothing directly to do with the LSD in it.

 

Another point of mine is that a lot crazier things has been done with success, and if this upgrade could be done "relatively easy", then why not, I could also ask ;-)

 

Besides that, I am guessing a lot of people on the puller scene would have wet dreams about a 1 1/8" rear end, with on the fly locking diff, or progressive LSD.

 

But I totally see your point. Problem for me is that I have a dream tractor, and it's red. And instead of swapping that out for something possibly green, I would rather see if I could overcome the shortcomings of my horse, so it could live up to that dream. Guess that is one reason among many, as why to get lured in by this hobby. :-)

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2 hours ago, Skipper said:

Another point of mine is that a lot crazier things has been done with success, and if this upgrade could be done "relatively easy", then why not, I could also ask ;-)

 

Besides that, I am guessing a lot of people on the puller scene would have wet dreams about a 1 1/8" rear end, with on the fly locking diff, or progressive LSD.

 

But I totally see your point. Problem for me is that I have a dream tractor, and it's red. And instead of swapping that out for something possibly green, I would rather see if I could overcome the shortcomings of my horse, so it could live up to that dream. Guess that is one reason among many, as why to get lured in by this hobby. :-)

 

Well since you put it that way, it makes more sense now!

Have to admit as I was also questioning the purpose or if it is worth the effort but like you wrote, " a lot crazier things has been done with success". "Problem for me is that I have a dream tractor, and it's red". That kind of thinking is understandable so it will be interesting to see how you progress with this.

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Thanks. It might not be rationel, perhaps not even sane, but.......

 

OK, so last night I turned this around a million times, and got to ask my self what perhaps should have been the first question of all. Would it be possible to mount a ring of spring steel in an 8 pinion, just like the 10 pinion has it? That would be the easiest fix. Does anyone have an 8 pinion laying open on the table, then pictures would be appreciated.  

Edited by Skipper

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There is no way to use the automatic locker setups or it's design in any wheel horse transmission. That requires a ring and pinion style gear configuration that uses existing spider gears and a carrier assembly - WH used a bull gear design with smaller gears traveling within the bull gear. The very early automotive transmission in the '65-'67 tractors only used a 2 pin differential - again, it will not lend itself to a locker as there is no room. Auto lockers of the ratchet type all have one thing in common in their operation - no axle is allowed to turn any slower than the ring gear. It can turn faster, but never slower. That is how they have a differential effect - when there is no driven load on one axle it can rachet faster than the ring gear. Anytime they are traveling in a straight line both axles are locked to the speed of the ring gear. In a turn, the outside wheel is allowed to spin faster than the ring gear, so it effectively drives the vehicle off the inside tire, somewhat opposite of an open differential. In the past years of wheeling I had run just about every differential design out there and broke most of them as well. By far the strongest and most reliable is the air lockers - but again, that requires a different design to the axle/gear carrier to make it work.

 

You're only real option would be a cable actuated differential lock - not an easy thing due to the bull gear design either. Or, if you're pulling that hard - a different and larger tractor. Most of us cure traction issues with weights/loaded tires/chains - ect....

 

Sarge

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3 hours ago, Sarge said:

There is no way to use the automatic locker setups or it's design in any wheel horse transmission. That requires a ring and pinion style gear configuration that uses existing spider gears and a carrier assembly - WH used a bull gear design with smaller gears traveling within the bull gear. The very early automotive transmission in the '65-'67 tractors only used a 2 pin differential - again, it will not lend itself to a locker as there is no room. Auto lockers of the ratchet type all have one thing in common in their operation - no axle is allowed to turn any slower than the ring gear. It can turn faster, but never slower. That is how they have a differential effect - when there is no driven load on one axle it can rachet faster than the ring gear. Anytime they are traveling in a straight line both axles are locked to the speed of the ring gear. In a turn, the outside wheel is allowed to spin faster than the ring gear, so it effectively drives the vehicle off the inside tire, somewhat opposite of an open differential. In the past years of wheeling I had run just about every differential design out there and broke most of them as well. By far the strongest and most reliable is the air lockers - but again, that requires a different design to the axle/gear carrier to make it work.

 

You're only real option would be a cable actuated differential lock - not an easy thing due to the bull gear design either. Or, if you're pulling that hard - a different and larger tractor. Most of us cure traction issues with weights/loaded tires/chains - ect....

 

Sarge

 

page 22, would one of those work?

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It might, if it could be widened to take the locker unit, but it might be easier just to build a new carrier to be honest. 

 

My priority right now for this is to see if a spring can be put into the 8 pinion. If not, I will try to get data on sizes of lockers and small progressive LSD's. Just learned they come in smaller size for atv/utv use also, so who knows what can be found out there. :-) 

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11 hours ago, Skipper said:

Thanks. It might not be rationel, perhaps not even sane, but.......

 

OK, so last night I turned this around a million times, and got to ask my self what perhaps should have been the first question of all. Would it be possible to mount a ring of spring steel in an 8 pinion, just like the 10 pinion has it? That would be the easiest fix. Does anyone have an 8 pinion laying open on the table, then pictures would be appreciated.  

 First pic is inside a 8 pinion  second shows one of Shawn's new springs sitting inside. 3rd has axle gear out in, Have no idea if it would function like it does in a 10 pinion...also have to come up with a spring tempering process as currently the new spring doesn't seem to be "springgy " enough

IMG_0127.JPG

IMG_0128.JPG

IMG_0129.JPG

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5 hours ago, Sarge said:

There is no way to use the automatic locker setups or it's design in any wheel horse transmission. That requires a ring and pinion style gear configuration that uses existing spider gears and a carrier assembly - WH used a bull gear design with smaller gears traveling within the bull gear. The very early automotive transmission in the '65-'67 tractors only used a 2 pin differential - again, it will not lend itself to a locker as there is no room. Auto lockers of the ratchet type all have one thing in common in their operation - no axle is allowed to turn any slower than the ring gear. It can turn faster, but never slower. That is how they have a differential effect - when there is no driven load on one axle it can rachet faster than the ring gear. Anytime they are traveling in a straight line both axles are locked to the speed of the ring gear. In a turn, the outside wheel is allowed to spin faster than the ring gear, so it effectively drives the vehicle off the inside tire, somewhat opposite of an open differential. In the past years of wheeling I had run just about every differential design out there and broke most of them as well. By far the strongest and most reliable is the air lockers - but again, that requires a different design to the axle/gear carrier to make it work.

 

You're only real option would be a cable actuated differential lock - not an easy thing due to the bull gear design either. Or, if you're pulling that hard - a different and larger tractor. Most of us cure traction issues with weights/loaded tires/chains - ect....

 

Sarge

 

Your way of describing how the locker works is spot on with my understanding of it. Well formulated.

 

I am aware the locker needs a carrier, but no one says how to drive that carrier, or what it should look like, as long as it could house that locker. We might as well fit our sprocket to it instead of a ring gear. With the rpm's it's going at, it does not need to be in perfect balance either.

 

Here is a picture of an LSD, with build in carrier. If that could be had in a size where our differential sprocket (is that the correct name, probably not) could fit outside it, and it could fit inside the box, it would be a matter of having some axles made to fit, and it should in theory work. 

lsd.jpg

Edited by Skipper
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13 minutes ago, pfrederi said:

First pic is inside a 8 pinion  second shows one of Shawn's new springs sitting inside. 3rd has axle gear out in, Have no idea if it would function like it does in a 10 pinion...also have to come up with a spring tempering process as currently the new spring doesn't seem to be "springgy " enough

 

Thanks so much for the pictures. That helped a bunch.

 

I do not see why it should not work the same. Are we sure there is room for it when the carrier is put together. (no rubbing or grinding)?

 

I see there is room to make the spring beefier, and I agree it is a matter of giving the steel the right treatment after fabrication to achieve the "springy" effect that we are looking for. 

 

If I can have the dimensions for that spring, and if you will let me know if the outside spring diameter is the same for 8 and 10 pinion units, I will try to contact someone I know that might be able to help out.

 

As I understand it, it is 4150 steel as base material. Is that correct?

 

Also, could you give me the inside dimention of the "sprocket" or carrier, that houses the 8 pinions. Where it is the narrowest please :-)

 

Thanks a lot. I appreciate your effort very much.

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You need to get the specs for the spring from Shawn he had them made.

 

out of idle curiosity I experimented a bit.  Without the spring and the differential with axles just sitting on the bench if you turn one axle by hand the other spins the other way and virtually no effort required to do the turning.  Putting the  spring in you cannot turn the axle at all, just like the 10 pinion responds just sitting on the bench.  Tomorrow I will substitute a junk axle with a nut welded on the end.  then clamping one axle in a vice try turning the axle with the nut using a torque wrench to see how much it takes to make slip.  Also see if there is any grinding.

 

Not sure what dimension you are looking for in your next to last line??

 

Edit:  since eh outer diameter of the axle gears about the same in 8 and 10 pinions (the gear teeth are NOT the same and are not interchangeable) I wold assume the spring would have the same outer diameter.  (Of course we all know what assume means:P)

 

Edited by pfrederi
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Wow that's good progress!

 

Sorry for being unclear about it. Problem is that I'm only a closet English speaker, so some words is just not in the vocabulary. So sometimes I just go for it instead of looking up the right word, and then it gets scrambled. My bad. :-)

 

What I meant was. That big gear, that circles the 8 pinions and axles, and to which you bolt the end peaces. If you take that out, and empty it for everything. Now, how big a diameter pipe would you be able to fit inside it? 

 

Not having had a unit in hand, I would take a guess that it might be close to 4 inches?

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Cocktail hour now I will measure it tomorrow.    One thing bothers me, if just adding a spring makes it work why didn't WH do it....

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