Ring gear bolts

[joeskylark]

My 1970 Buick Chassis manual states that for 1970 Skylark 10 bolt rears use 7/16" left-hand thread ring gear to carrier bolts. Several non Buick sites declare that the best way to determine whether or not a 10 bolt rear is an 8.2 or an 8.5 rear is to remove a ring gear bolt. If it is an 8.2, it will be right hand threaded, and if it is an 8.5, it will be left hand threaded. What is true? I am trying to buy an 8.5 rear because it is cheaper to re build than an 8.2. The rear I am going to look at is in a 1972 Buick Skylark Sun Coupe.I just want to quickly verify that it is an 8.5 when I go look at it because the seller cannot verify that it is the original rear. Thanks. -Joe

 

[bob k. mando]

i don't know about the LH vs RH bolt thing, but if you get the 3 letter axle stamp off of the front of the passenger side axle tube it can be decoded to tell you what size ring gear, gear ratio and open / LS diff was originally in the car.

take a wire brush and a piece of chalk with you.