Typhon Why is the top of the input gear rubbing against my differential ?

[DavefromCA]

For the life of me, I cannot get this right, just rebuilt two rear ends with new parts, but in both instances, the input gear is against the differential and it does not spin freely. The only way to get it somewhat free is to not tighten the yoke screws. Are these plastic yokes the issue? I’ve always been in the opinion, the plastic parts are fine, if they break something is out of whack, but these diffs just are not spinning right.

 

[Big Kid]

Please define WHAT DIFFS ?

Sounds like your speaking 3S or 4S models diff's ?

 

[DavefromCA]

3s rear plastic diff

 

[Johnny b]

Proper shinning of the diff is important to ensure the right input to diff mesh. I had the yokes warp on my 3s cars and switched to hot racing alloy yokes.

 

[DavefromCA]

So the shims go on the sides of the diff? And that backs it away from the input?

 

[Johnny b]

So the shims go on the sides of the diff? And that backs it away from the input?

That is correct. It either backs it away or brings it closer, depending on which side of the diff you shim.

 

[DavefromCA]

Wow I am glad you included that last detail, guess I’ll start looking for shim kits, thank

 

[Johnny b]

With the stock plastic diff components, there may be some initial tightness and a wear in time period but it should not be excessive. Play with those shims until you get a nice mesh.

 

[DavefromCA]

Is

ARR709052 the right part number?​

 

[Neelis]

Is

ARR709052 the right part number?​

Yes sir.