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Well hopefully I can get this working and do the same as you are planning, make a kit that can be dropped into a Rhino.

Unfortunately I was out bid on that wrecked Grizzly. I will buy a used Grizzly front differential and actuator off eBay this week.

Edit (10 min later):
I bought it, I couldn't wait haha. I think I found a good deal, $349/diff and $99/actuator.
Nice! If it does not work, you can always resell it on ebay.

I do not see a huge market for the diff swap. However, if you can put together a bolt in "kit" you may at least be compensated for your time and investment.

Live axles, with aggressive tires, will really tear up a nice lawn.
 

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Discussion Starter · #42 ·
Well I finally got some time in yesterday to work on it. Pulled the rear diff out of my Rhino and wow they are TOTALLY different.

The front diff is much smaller, I would not want to try to make that fit in the rear end, it just looks too weak.

Right now it looks like I am going to have to make a complete rear differential. I think it might end up a little wider than the current one so I will try to make it so the passenger axle (currently longer) will be replaced with another driver side axle. Use a OEM diff lock motor and make a wiring harness to use the same safety's as the current front diff lock motor, just add another switch on the dash to lock the rear.

Comments, questions, concerns, and critiques appreciated!

Lots of work ahead!
 

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Discussion Starter · #44 ·
I think it might end up a little wider than the current one so I will try to make it so the passenger axle (currently longer) will be replaced with another driver side axle.
Would this require moving the A-Arm frame pivot locations the same amount?
I don't think so. Are the rear driver and passenger a-arms the same size? If so then having both sides use the same size axle as is currently being used on the driver side would work well.
 

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Discussion Starter · #45 ·
Here is the front diff I bought (left) and the rear diff out of my rhino (right)
 

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Discussion Starter · #46 ·
I have been working on another project so this one got put on hold for a bit. (Ford Ranger Diesel conversion :biggrin: )

I got to this the other day though and started building an open diff. Just the guts, that will fit inside the current housing. I don't think I can make a strong enough locking diff using the current housing.

So open diff for now, that will solve my problem of tearing up the lawn and driving like crap on the street.

Then open diff with locker later, that will be a whole housing as well.
 

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........... So open diff for now, that will solve my problem of tearing up the lawn and driving like crap on the street.

Then open diff with locker later, that will be a whole housing as well.
Sounds like a plan. Keep us posted as to your progress. This will be of interest for a lot of us.
 

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Discussion Starter · #49 ·
Yes but not there yet. It has been a lot of work, many hours on the computer. I am getting close to ordering some parts from machine shops for the first prototype.
 

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Yes but not there yet. It has been a lot of work, many hours on the computer. I am getting close to ordering some parts from machine shops for the first prototype.
GET A PATENT!

I would hate to see Yamaha (or anyone else) steal your design and sell it to the side by side crowd.

One of my buddies obtained a patent, without a lawyer, for some gold prospecting equipment he designed. If you want, I can ask him how he did it.

You have a good idea and worked hard to get it to this point. Don't let some azzhole steal it from you.
 

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Discussion Starter · #51 ·
GET A PATENT!

I would hate to see Yamaha (or anyone else) steal your design and sell it to the side by side crowd.

One of my buddies obtained a patent, without a lawyer, for some gold prospecting equipment he designed. If you want, I can ask him how he did it.

You have a good idea and worked hard to get it to this point. Don't let some azzhole steal it from you.
I have been thinking about it, maybe once it is done I will and if I need help I will definitely PM you, thanks!
 

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Discussion Starter · #53 ·
Any other progress on this? I'm getting a LOT of grief from the wife about what used to be our yard.
Sorry for the late replay.

Yes a lot of progress, I have the differential built and in my Rhino right now! :banana:

I am just working on making the axles and drive shaft fit and then I can test drive it.

Check out my facebook page Sgroi Innovations to see pictures and stuff. If I am not allowed to write that please remove it, I don't want to get in trouble on this great forum!
 

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GET A PATENT!

I would hate to see Yamaha (or anyone else) steal your design and sell it to the side by side crowd.

One of my buddies obtained a patent, without a lawyer, for some gold prospecting equipment he designed. If you want, I can ask him how he did it.

You have a good idea and worked hard to get it to this point. Don't let some azzhole steal it from you.
I have been thinking about it, maybe once it is done I will and if I need help I will definitely PM you, thanks!
To get a valid and enforceable patent, it must be novel and not a usage of known art for the same purpose at a slightly different location. Your CAD model does not look like it is a "differential" but rather an engagement/disengagement for driving one side. This ends up being one wheel drive when "open". This is essentially the same thing as the Yamaha front locker (which is not a true differential either). I would expect that you would have a hard time getting a patent for its use on the rear end.

This is not to discourage you, but rather to encourage you to involve a patent lawyer to evaluate the validity of your "claims" before investing the time and money in filing for a patent.
 

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Isn't the rear differential a posi and not a locker?
If you are asking about the Rhino family rear drive, it is a spooled axle. A direct connection from wheel to wheel ("spool") with a ring and pinion to couple the driveshaft from engine to the spool. So, it is not a differential.

The classic differential has a bevel gear at each of the axle shafts going to the wheels. Between the faces of those bevel gears there are smaller bevel gears at right angles to the axle shafts. These smaller bevel gears are mounted into a carrier that can spin on the same axis as the axle shafts and is driven by a ring and pinion which couples torque from the engine into the carrier.



With this differential, when you go around a corner the outer wheel rotates further than the inner wheel. What happens then is that the axle shaft bevel gears counter rotate with respect to each other which causes the cross axis bevel gears to turn within the carrier. Since the carrier rotation is not affected by the turning of the vehicle, it is still able to transmit torque to both wheels throughout the turn.

That was an "open" differential. It one wheel has no traction it will spin freely and the opposite wheel does not receive any torque to propel the vehicle forward. Positrac (limited slip, etc.) essentially adds friction clutches to couple the axle shafts to each other such that torque can be transmitted to the wheel that still has traction in spite of the spinning wheel on the other side. In the corner, the clutches slip such that the wheels can rotate at different rates. This is sort of a compromise in traction vs. ease in turning. Locking differentials simply mechanically lock the axles together and provide no counter-rotation ability to smoothly negotiate the corner unless they are in the un-locked mode. These are essentially only intended to be used off-road on loose driving surfaces: Such as manicured lawns and the like, much to the dislike of the turf maintenance person. :)
 

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To expand on this subject a bit, the Yamaha Rhino family front drive is not a differential either. It is sort of a double acting locker. It has the ring and pinion coupling from engine drive shaft to the internal spinning mechanism as well. When you are in 2 wheel drive mode the internal spinning axle stuff is altogether decoupled from the ring and pinion. When you switch to "4WD mode" one front wheel is hard coupled to the ring and pinion. This is actually a 3 wheel drive situation, but does decouple the front wheels from each other. The difference in rotation in a turn is much more pronounced on the front (steering) wheels than it is at the rear (trailing) wheels, so this greatly reduces the steering effort and possible kickback that would happen if both front wheels were fully locked together.

For increased traction on loose terrain, at the expense of drivability, putting the front drive in 'locked mode' hard couples both front wheels together. This is the true 4 wheel drive mode for these machines. It takes a bit of caution while driving in this mode as the machine definitely resists your efforts to turn it through a corner. Unequal traction on either side of the front wheels can result in a violent spinning of the steering wheel, etc., etc.
 

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Discussion Starter · #59 ·
Isn't the rear differential a posi and not a locker?
If you are asking about the Rhino family rear drive, it is a spooled axle. A direct connection from wheel to wheel ("spool") with a ring and pinion to couple the driveshaft from engine to the spool. So, it is not a differential.

The classic differential has a bevel gear at each of the axle shafts going to the wheels. Between the faces of those bevel gears there are smaller bevel gears at right angles to the axle shafts. These smaller bevel gears are mounted into a carrier that can spin on the same axis as the axle shafts and is driven by a ring and pinion which couples torque from the engine into the carrier.



With this differential, when you go around a corner the outer wheel rotates further than the inner wheel. What happens then is that the axle shaft bevel gears counter rotate with respect to each other which causes the cross axis bevel gears to turn within the carrier. Since the carrier rotation is not affected by the turning of the vehicle, it is still able to transmit torque to both wheels throughout the turn.

That was an "open" differential. It one wheel has no traction it will spin freely and the opposite wheel does not receive any torque to propel the vehicle forward. Positrac (limited slip, etc.) essentially adds friction clutches to couple the axle shafts to each other such that torque can be transmitted to the wheel that still has traction in spite of the spinning wheel on the other side. In the corner, the clutches slip such that the wheels can rotate at different rates. This is sort of a compromise in traction vs. ease in turning. Locking differentials simply mechanically lock the axles together and provide no counter-rotation ability to smoothly negotiate the corner unless they are in the un-locked mode. These are essentially only intended to be used off-road on loose driving surfaces: Such as manicured lawns and the like, much to the dislike of the turf maintenance person. :)
To expand on this subject a bit, the Yamaha Rhino family front drive is not a differential either. It is sort of a double acting locker. It has the ring and pinion coupling from engine drive shaft to the internal spinning mechanism as well. When you are in 2 wheel drive mode the internal spinning axle stuff is altogether decoupled from the ring and pinion. When you switch to "4WD mode" one front wheel is hard coupled to the ring and pinion. This is actually a 3 wheel drive situation, but does decouple the front wheels from each other. The difference in rotation in a turn is much more pronounced on the front (steering) wheels than it is at the rear (trailing) wheels, so this greatly reduces the steering effort and possible kickback that would happen if both front wheels were fully locked together.

For increased traction on loose terrain, at the expense of drivability, putting the front drive in 'locked mode' hard couples both front wheels together. This is the true 4 wheel drive mode for these machines. It takes a bit of caution while driving in this mode as the machine definitely resists your efforts to turn it through a corner. Unequal traction on either side of the front wheels can result in a violent spinning of the steering wheel, etc., etc.

Great explanation Steve! I have explained this to my father many times but not nearly this good!

So my rear differential is a true open diff with a locker, it now looks totally different than the CAD drawings in this thread. I hope to be testing it out very soon!
 

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Great explanation Steve! I have explained this to my father many times but not nearly this good!

So my rear differential is a true open diff with a locker, it now looks totally different than the CAD drawings in this thread. I hope to be testing it out very soon!
Thanks. More power to you with your design effort. Do keep us posted as you are certainly headed in the right direction.
 
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