Allis 917 hydro simplicity 7117 limited slip

[rjobkar]

From everything I have read tells me that my allis chalmers 917 hydro has limited slip. The only problem is when one wheels spins, it keeps on spinning, the limited slip seems to never work. I've owned this tractor for about two years, and the limited slip never worked. I have some experience with automotive limited slips, but not the simplicity/allis chalmers rear ends. Could someone please help me. I've searched on here but can't seem to find the help I need. Can anyone recommend some tips to look for or to try? An can someone maybe please explain how the limited slip actually works? I have downloaded the parts manual, and can see the parts, but I don't see what I would need to check or adjust. Thanks for the help.

[sunrunner]

Never heard of a hydro with limited slip? But that's just me:D

[Dark]

slip ring design, pressure on the plastic bushing from threaded lock screws causes the friction desired to make the axle a control traction design the bushing is plastic and that it causes friction when tightened on the inner tube axle but can slip when the force is greater then the torque of the collars friction so basically the inner tube is drive the outer tube driven the coupler in between is the plastic bushing that is causing friction that allows the tube to turn with the torque of the drive. It is not a real limited slip differential it can turn unlike an automotive that has clutches the design is just a slip bushing

[rjobkar]

Thanks for the information. Now it makes sense as to how the limited slip works. Can someone confirm SunRunners statement about hydros not having limited slip? That would solve the mystery.

[UCD]

Yes the hydro's have limited slip. All large frame Simplicity made tractors have limited slip. Also it is not the old RBT style described by Dark. The RBT and some late FDT's the limited slip is controlled by springs in the differential. Rod Hubbard knows these differentials inside and out and Can explain them the best. I wish people would read the Question and know what they are responding to before they give Misleading information. Some times it is bad enough when the manuals are not correct.

[CarlH]

The 7000/7100 series Sovereigns with hydro trannys have a differential with limited slip capability. This is the same differential assembly that is used with manual and variable trannys on these series tractors. The amount of limited slip is somewhat adjustable by shimming the springs inside the differential.

[HubbardRA]

I shimmed one for garden tractor pulling with standard 1/4 inch washers from a hardware store. I had to grind down part of the outer diameter of each washer so that they would fit within the diameter of the diff housing. I assembled the diff by using longer bolts than factory. Then when it was completely together I removed the long bolts and re-inserted the factory bolts one by one so that the diff could be re-assembled to the torque tube properly. This diff will usually spin both wheels when pulling a load, but will make a turn without slipping one wheel and tearing up the lawn. That diff was originally from an AC716H but was installed, along with the axle and right hub, into my 61 Wards (Simplicity 700) which originally had the old type diff with the nylon pads and the screws that you tightened to put pressure on the pads. I like the limited slip much better.

[Dark]

thanx for the correction UCD :o)

[sunrunner]

Now I have heard ......sm06