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Skipper

Thoughts on upgrading 8 pinion diff to LSD or Lock

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Well if I had to guess, probably because someone at wheel horse felt it was unnecessary, or that it might put more strain on things than they were ready to back with a warranty............... Who knows, But there are tons of items around every one of us, that were also made as a compromise, and not in the ultimate way. That's just the commercial nature of things, and that does not make it wrong to seek improvement ;-)

 

Oh and my gut feeling is, that if the spring is compressed just about the same in the 8 and the 10 pinnion diff, the 8 pinnion layout will have a stronger LSD force both static and dynamic. Looking forward to your testing :-)

Edited by Skipper
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3 hours ago, pfrederi said:

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.

 

That's sweet if it doesn't grind and certainly the simplest solution if it works

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If you were asking about possibly using a bevel gear WH differential to try to install a locker into it - no, there is just not enough physical room and carrier itself is the wrong shape to make it work. The locker parts would have to be very small - so small there is no way they could withstand the torque of what a tractor could put against the locker. The design of the tractor transmissions and differentials are very compact and for their size they are extremely strong. About the only other choice would be to use a different transmission setup and separate axle assembly, such as in a truck. That would require altering the tractor to the point of it being completely custom. 

 

I'm not knocking your idea and there is a chance the 8 gear unit could be altered, but not sure how you can get enough strength within the confined space where those gears sit without weakening the bull gear.

 

Sarge

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Made a couple of quick vids (my camera only does 30secs).

 

This is an 8 pinion with one of Shawn's new springs inside.  The readings I got are similar to those i got doing the same thing on a 10 pinion.  No apparent clearance issue.   I have watched a couple of youtubes on spring tempering.  May try that on one of the new springs as they do not generate as much resistance as an original albeit worn gouged springs.

 

Any guys here experts on tempering??  Actually any experience/knowledge at all is a lot more than I have.:P

 

Real test is to put it in a tranny on a worker and see what happens but would rather have a better spring before that much work.

MVI_0131.AVI

MVI_0132.AVI

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Chiming in on this thread as well (We should probably pick one to put all our data on)!

 

@Skipper has PMed me some good information on tempering. I just emailed the machinist that made those springs to see if he has the enthusiasm to continue (he does have the ability to temper). If we are looking at 8 pinion mods as well as 10 pinion rehabs, I'd think we may need another spring rate (less pinions, less friction to lock). Skipper, and others who are using their Horse for plowing and hauling rather than mowing, may also want a stiffer diff anyway - this would require some work. Perhaps a first round of engineering with testing like @pfrederi did, and then testing in various transaxles?

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Update: the machinist wants another crack at it before he passes it off! I’ll wrangle up the pieces for a spare diff and get it to him early next week. We’ll start with tempering (maybe shoot to go from 25 as is to 100 in-lbs with tempering as pferedi measured for a first target).

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The original size of the new springs is probably correct, problem is they bend inward and do not recover.  if he can temper them some they should work great.

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On 10/01/2018 at 7:52 PM, Skipper said:

 

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. 

 

shucks!  :wub:

 

thanks...

 

-------------------------------------

 

A bit late to this, but I went through the same issue of one wheel spinning when I needed them to be locked.

 

If I had to retro fit and keep the 8 speeds (I lost the gearbox on mine, it's tight in there) I would look at doing it externally.

 

The other two ways that were on the list were:

 

1. Add independent brakes on the hubs like a D-series - that way you can brake the spinning wheel

2. Add a pulley to each hub connected to a counter shaft by belts and just tension the belts to lock the wheels. This one is probably easier and can be set to anything between fully locked and some slip.

 

 

 

 

Edited by meadowfield
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On 12/1/2018 at 3:16 PM, Sarge said:

If you were asking about possibly using a bevel gear WH differential to try to install a locker into it - no, there is just not enough physical room and carrier itself is the wrong shape to make it work. The locker parts would have to be very small - so small there is no way they could withstand the torque of what a tractor could put against the locker. The design of the tractor transmissions and differentials are very compact and for their size they are extremely strong. About the only other choice would be to use a different transmission setup and separate axle assembly, such as in a truck. That would require altering the tractor to the point of it being completely custom. 

 

I'm not knocking your idea and there is a chance the 8 gear unit could be altered, but not sure how you can get enough strength within the confined space where those gears sit without weakening the bull gear.

 

Sarge

 

I was thinking in the lines of building a carrier from scratch to house the locker :-)

 

Lets see how it goes with the spring LSD solution for 8 pinion trans. If that works good, no need to go down this road.

On 12/1/2018 at 8:02 PM, sfjohnson722 said:

Update: the machinist wants another crack at it before he passes it off! I’ll wrangle up the pieces for a spare diff and get it to him early next week. We’ll start with tempering (maybe shoot to go from 25 as is to 100 in-lbs with tempering as pferedi measured for a first target).

 

Sounds really good, but remember in the hardening process, that you need the tempering afterwards to make sure the spring is softer than the pinion. If that goes well, it should be as simple as selecting thicher raw stock and make more and stronger springs :-)

On 12/1/2018 at 8:11 PM, pfrederi said:

The original size of the new springs is probably correct, problem is they bend inward and do not recover.  if he can temper them some they should work great.

 

They have not been hardened, so yes, they will do that. :-) Lets cross our fingers that a hardening and tempering will do the trick.

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1 hour ago, meadowfield said:

 

shucks!  :wub:

 

thanks...

 

-------------------------------------

 

A bit late to this, but I went through the same issue of one wheel spinning when I needed them to be locked.

 

If I had to retro fit and keep the 8 speeds (I lost the gearbox on mine, it's tight in there) I would look at doing it externally.

 

The other two ways that were on the list were:

 

1. Add independent brakes on the hubs like a D-series - that way you can brake the spinning wheel

2. Add a pulley to each hub connected to a counter shaft by belts and just tension the belts to lock the wheels. This one is probably easier and can be set to anything between fully locked and some slip.

 

 

 

 

 

Your point one and two has actually already been on the drawing board :-) And yes, they are solutions to pursue, if a good LSD or Locker is not found for the diff. Racinbob suggested the side breaks to me a while back, and I had the idea floating on doing it with pulleys. So I guess we have had thoughts in similar directions. Hope it means all hope is not lost yet ;-) 

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2 hours ago, meadowfield said:

Add a pulley to each hub connected to a counter shaft by belts and just tension the belts to lock the wheels. This one is probably easier and can be set to anything between fully locked and some slip.

Guess you could spring load the counter shaft to allow some slippage for cornering and a foot peddle or lever with over-center locking to lock it down as needed.

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On 1/11/2018 at 3:10 AM, Skipper said:

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

 

THAT'S a good enough reason for many right there......

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