captng1

I have got too much backlash between my ring gear and pinion gear (0.015) Right now I can pull the posi case in and out with ease, really no resistance. I have seen in videos that you are supposed to have a tight fit on the shims and need to tap the shim in with a hammer or plastic mallet. I am going to a slightly thicker shim to decrease the backlash to .008 My question is if you tap in the shim and the backlash is still not right and you have to remove the posi case again, how do you get it back out if it is tight? I guess you would need to pry it out, but where is the best place pry from?
Thanks

Fly skids up!

I've have pry them out before. No biggie. I have to ask, are those used bearings that you're trying tighten up the preload with a shim? If yes you should replace those bearings because if they are that loose they are probably worn.

captng1

Hello Fly Skids Up,
Yes the bearings are used, but appear to be ok. I am not trying to tighten up the preload, I am trying to tighten up the backlash. It is too big. Putting in new bearings will not tighten the lash. Also I get different measurements at different positions off the ring gear. I assume this is due to ring gear run out. Do you know how many thousandths of ring gear run out is acceptable?
Thanks,
Gary

David Mc

Ring gear runout should be less than .001

Yes, the side bearings need preload too. Shim to you get to zero lash and add .002-.004 to each side.

Fly skids up!

Well here's the thing. When that diff was new it would not side in or out of the housing with the ease. So now that it does those bearings/races are missing about .008" of metal now. So I would definitely replace those bearings while you got it apart. Rockauto has them for $12-14 a piece. And it possible that a worn bearing could help with the backlash and runout too.

captng1

Thanks David,
I am told that you want to have about .005 -.008 of lash, not zero......

captng1

Thanks Fly Skids Up,
I agree. Unfortunate I don't have a press. I guess I can take it to a shop and have them press new bearings on. David above is telling me to get the lash to zero and then add another .002 - .004 of shims to both sides. I have been told when set up properly I should have between .005 - .008 of lash. Do you agree?

Fly skids up!

I think he meant zero carrier movement in the housing. You always need some sort of backlash when setting up any kind of gear. I have a 20 ton press that you could use, if you feel like driving to north Florida.

captng1

Ha! Thanks man... David did use the exact term "Lash" which is what confused me and I was not in agreement with. There is no side movement in the carrier at this time, just no preload, but I need to get rid of about .006 -.007 of lash. I guess I will change the bearings first and then check the ring gear runout before checking and setting final lash...