Limited slip diff....

[SunkenMetal]

So I have been thinking about making a limited slip or posi traction whatever you want to call it diff for my savage. But I wanted it to be adjustable so I can tune the diff with out having to take off the bumper and the screws to remove the diff cover and take out the diff. so I figured a set screw in one of the output cups to put pressure onto the spring inside the diff. That way you just have to remove the dog bone to tune your diff. instead of removing the diff taking the diff apart cleaning out the diff silicone, then putting it back together with a new weight silicone.

Or, use 2 wedges and a set screw threw the diff cup to adjust the tension on the spring… anyways I am brain storming, and drawing it up so I can see my ideas and work out any problems before I start drawing things to scale…

Here is what I have come up with so far...

I am to lazy to label everything in the drawing, and it’s a pain to do in Mastercam, I just color coded everything and here is a key to what everything is in the drawing

White=Bearings
Red= output cups
Brown= spring tension set screw
Green= Diff Gear
Grey=Diff cup
Blue=Friction discs
Yellow= Spring

Pretty much the only thing that would be stock is the Gear… I have made gears before but I just don’t feel like drawing it up or doing the math, I am lazy like that…..

So what do ya think of my idea, or has someone tried it, or sell it already.

 

[Bankrupter]

I think the friction disks need to be larger but your on to something.

 

[SunkenMetal]

I think the friction disks need to be larger but your on to something.

Yeah this is just a perliminary drawing just putting my idea out there so i can see better what I'm planning... yeah i was thinking the same thing..

 

[Shaun]

hmm thats a really interesting idea, keep us informed as to how your making out with that

 

[backwoodboys11]

well back several months ago i busted 2 spider gears in the rear diff, i didnt have the money to fix it the right way so i broke out the good old lincoln welder.
to this day it is still like that and the weakest link now is the dog bones.
i also run real thick oil in the front so going straight its locked but turning it will slip

 

[Blazer X]

Well it would be fun to tinker with, reliability would be a factor with the heat and general abuse they take.

 

[Neohio]

I know you say it is a very basic drawing.

I cannot tell how the drive cups are going to be attached to the slipper plates? 1:1 stuff is splined, but to do that will get costly. I haven't really torn my diffs apart yet, so I'm definitely not familiar with how they connect to the spiders right now.
I'm thinking maybe you can use a cross shaft and a 14mm hub to use for the basis of the slipper part?

 

[AllanQ]

Sunk, I am not a mechanical engineer, but I am not understanding how the screws will go all the way through the drive cup, adjust the spring inside and still get power to the dogbones. I do not think there is a lot of room to drill the center out of the drive cup without loosing a lot of strength, and you will end up drilling through the inside pin holding the drive cup shaft to the gear. I know you do not want to remove the diff cover, but is there a way to do what you have drawn up except to put the screws though the side of the diff cup, using a set screw or a grub so it does not interfere with the pinion? You can drill a small access hole in the diff cover and go through the front for adjustments, and put a small rubber cover to keep out the dirt and grit. I think you are on to something good, but I am just having difficulty putting it together in my head.

 

[SunkenMetal]

Well it would be fun to tinker with, reliability would be a factor with the heat and general abuse they take.

Ah it would be reliable, its simple. Its always been my belief that the more simplified something is the more reliable it is....

I know you say it is a very basic drawing.

I cannot tell how the drive cups are going to be attached to the slipper plates? 1:1 stuff is splined, but to do that will get costly. I haven't really torn my diffs apart yet, so I'm definitely not familiar with how they connect to the spiders right now.
I'm thinking maybe you can use a cross shaft and a 14mm hub to use for the basis of the slipper part?

I have a few ideas, this is just one idea on how to make it adjustable. i have another idea how to make it adjustable where you don't have to take anything off the savage, similar to the way you adjust the transmission pull out a rubber plug and adjust...

Also i didnt want to throw up a complete drawing that is to scale or with tool paths on it. it might end up being made by someone else.....

 

[SunkenMetal]

Sunk, I am not a mechanical engineer, but I am not understanding how the screws will go all the way through the drive cup, adjust the spring inside and still get power to the dogbones. I do not think there is a lot of room to drill the center out of the drive cup without loosing a lot of strength, and you will end up drilling through the inside pin holding the drive cup shaft to the gear. I know you do not want to remove the diff cover, but is there a way to do what you have drawn up except to put the screws though the side of the diff cup, using a tapered screw head so it does not interfere with the pinion? You can drill a small access hole in the diff cover and go through the front for adjustments, and put a small rubber cover to keep out the dirt and grit. I think you are on to something good, but I am just having difficulty putting it together in my head.

there are other materials out there that will handle what I'm saying here. the shaft wouldnt be the same as stock... imagine a slot and a hex with a doll pin.....

as for what your sugesting i thought of that to about the plug and side screw. I'm working out a different idea for that....

pretty much the only thing that would be stock savage is the gear, modified to fit a larger diameter shaft....