Slipperential Binding (center diff)?
 

Guys, having some slight issues with my slipperential center diff. Assembled per instructions including the o-rings behind the small spiders but the diff doesn't run smooth at all. it will actually bind if I try to spin just one outdrive while holding the spur.

I ended up adding a second diff cover gasket with no real improvement. I then pulled the o-rings from behind the spiders and pulled the second cover gasket and that seems "slightly" better. Pulled the whole thing down a 3rd time to give it a full inspection but not seeing anything out of place. Gears all look clean. No damaged teeth...

Haven't run this yet so it should break in some but it certainly is no where near as smooth as the OE center diff I pulled (also not run).

Originally, when I assembled one of the drive pins was too long and required cutting down to fit within the large spider. The fit is still tight but doesn't seem like there are any issues with it not seating.

Anyone have any thoughts? Planning on running it as is and seeing how it works out as I don't think it'll be too big an issue but will certainly affect the "feel" of the diff and how power is applied.

Thanks.

What weight oil are you using? And the spider gears you have are 10T and 20T right?

Maybe try assembling without the small spider o-rings.

10k oil in the center diff.

No one has any ideas here?

Are the internal gears binding from being too tight, or too loose? If adding another gasket doesn't make an improvement, try going the other way (perhaps leave off the oil and one gasket altogether to see if it is smoother). The diff should not bind when spinning an out drive, so something is definately wrong - just need to find out what the something is.

I've noticed that the slipperential housing (the threaded part which also has the grooves that the spider gear shafts key into) has many little veins/slots.

Considering the OP had to cut down one of the spider gear shafts, is it possible that he keyed the spider gear shafts into the wrong slot - thus causing binding?

Na, the cross pin for the large spider was a touch long so I just took off .080'ish from it. So it's not the small spider cross pin/pins. They are all properly located within the diff housing....


Mike,

I did pull the gasket and it did seem to feel a little better so might be a touch on the loose side possibly. That being said, one would assume the addition of the o-rings behind the small spiders would decrease the clearance between the small/large spiders and it "should" have gotten better/smoother. Thus far, that hasn't been the case.

Like I said, I got it pretty well sorted. I'm going to run it a touch and see if things smooth out some. I've built a million (maybe not a million but significant) 1/8th scale diffs and this isn't any different from an assembly standpoint. Just seems there a little something going on in there clearance wise.

Stay Tuned -