Granite Rebuilding 3s diffs.

[Closey]

How do I get the spinning freely. I have run every combo of shim. Currently have 4 on the cup side and 1 on the gear side, with the yoke ever so slightly loosened it spins nice but anything else feels like it is getting caught up.

All new bits, yokes, input, bearings, diff cup and cap, internals spin fine(I filled them up). The yokes are on the right way.

No matter what it doesn't want to spin freely.

 

[Velodromed]

How do I get the spinning freely. I have run every combo of shim. Currently have 4 on the cup side and 1 on the gear side, with the yoke ever so slightly loosened it spins nice but anything else feels like it is getting caught up.

All new bits, yokes, input, bearings, diff cup and cap, internals spin fine(I filled them up). The yokes are on the right way.

No matter what it doesn't want to spin freely.

Assuming you assembled it right…

Check to make sure the bearings are pressed all the way on. I set on a socket and tap them on with a rubber mallet. Press would work even better but don’t have one.

When I fill them I go 3-4mm from top and make sure to not get oil in the pin or screw holes as it messes them up during reassembly.

I rarely use more than one shim. When new I’ll put one opposite the ring. As it wears I’ll switch it. With hot racing yokes I usually don’t need one at all. When putting in the yokes there’s no need to crank them on. Just finger tighten. I lightly grease the ring and input gear with a synthetic grease like superlube. No need to go overboard just rub it in the plastic gears to coat well.

Good luck man.

 

[Closey]

Assuming you assembled it right…

Check to make sure the bearings are pressed all the way on. I set on a socket and tap them on with a rubber mallet. Press would work even better but don’t have one.

When I fill them I go 3-4mm from top and make sure to not get oil in the pin or screw holes as it messes them up during reassembly.

I rarely use more than one shim. When new I’ll put one opposite the ring. As it wears I’ll switch it. With hot racing yokes I usually don’t need one at all. When putting in the yokes there’s no need to crank them on. Just finger tighten. I lightly grease the ring and input gear with a synthetic grease like superlube. No need to go overboard just rub it in the plastic gears to coat well.

Good luck man.

Thanks. I got it mostly to my liking. They do seem finicky though.

 

[Michael24]

finicky is ok last time rebiult 3s diff i used all stock metal instead of the exb module. endened up using 6 or 7 shims altogher. was't the smoothest after a couple months use it wearing perfectly.

 

[GRC]

Because you are using way too many shims. Of course it binds when you try to tighten the yoke. The purpose of shims is to fill loose space inside the yoke. You have no loose space, you can't even close the yoke. I've also only needed one shim on the 3s diff. What is your goal using that many shims?

 

[Closey]

Because you are using way too many shims. Of course it binds when you try to tighten the yoke. The purpose of shims is to fill loose space inside the yoke. You have no loose space, you can't even close the yoke. I've also only needed one shim on the 3s diff. What is your goal using that many shims?

I said I had used all different combos of shims. I get that it is too much, I was playing around to try to get it spinning smother.

 

[RCbuzz]

I don't think I have ever needed an *additional shim on the 3S line diffs.

 

[GRC]

Definitely check that the bearings on the side of the differential are pushed all the way down to the sides of the diff. As Velodromed said, it can take some hammering with something that only pushes the bearing but leaves the middle hole open for the diff to come through. I use a wrench that's opened enough to push the bearing but leave the hole open.

Check that the diff bearings as well as the input gear bearings are rolling smoothly. The only other tip I would give is check the gear teeth of the diff and input gear. Pay close attention to where you feel snags and check those teeth for damage, warping, dirt, excessive grease.

 

[basher27]

One shim opposite the gear side.

 

[ksearyback]

Thanks. I got it mostly to my liking. They do seem finicky though.

What did you end up adjusting to get it to your liking? I'm learning all of this stuff now, and putting the diff back together without any binding, and where the gears / drive trains rotate smoothly has proven impossible for me thus far.