Been a mechaniic for 45 yrs and learnned something new today

[BCOWANWHEELS]

Well decided to install a eaton posi in my old 70 c-10 so went about it like all the dozens or so i,ve done in prior years. Got the open diff out, got my trusty carrier bearing puller out and installed,pulled one side and to my amazement "no" shims. I scratched my old head and pulled the other side and "no" shims there also. Never seen any brand of diff that setup with shims not have any..... Rear had never been openned up ever. Well got me brand new eaton posi out,cleaned up and decided to start with "no" shims. Sure enough it set right up with no shims pattern was perfect,backlash was 1 thou. "less" tighter......
Man sure wish all was this easy. Never too old to see something new or learn...........

[doo142]

Nice!! Take it while you can!!!

[Redline novdog]

Aah yes when machine tolerances stack on the good side!!!! Very rare I say!

[bad68nomad]

It should have had a spacer on each side of the carrier. Those are the factory shims. When you buy an install kit it comes with shims so you can move it to set backlash if necessary. Most times the factory spacers will get you really close. One thing I usually do is throw the crush sleeve away and install a solid pinion spacer. Then you dont have to worry about overtightening the pinion nut and tightening up the pinion bearings.

[BCOWANWHEELS]

yes it had the factory shims on the outsides of carrier bearings. I just swaped over the ring gear and didn't have to mess with the pinion gear. rear only had 19 k on it. the 3,73 gears are perfect for my use with 3 on the tree.

[Tony]

I'm no expert but have changed a few GM gears and it's hard to imagine GM or Eaton getting tolerances that close...Many years ago a friend had a differential gear failure in a Datsun...No shims but three different ring and pinion sets to fit the tolerances...Of course the set you needed was never in stock..

I work on older Jeeps with Dana axles and the shims are between the carrier bearing and the carrier...A real time consumer to pull bearings to make shim adjustments...

[Keith Seymore]

Originally Posted by Tony

I'm no expert but have changed a few GM gears and it's hard to imagine GM or Eaton getting tolerances that close...Many years ago a friend had a differential gear failure in a Datsun...No shims but three different ring and pinion sets to fit the tolerances...Of course the set you needed was never in stock...

That's the beauty of statistical variation and high volume production - one out of every million or so will be "perfect", whether you planned it that way or not.

K