GM 8.5" Olds "O" Axle 3.90 Ring & Pinion 31 Spline Posi Gear Pkg

Richmond Gear is the leading manufacturer of professional-quality, high performance ring and pinion sets. The superior quality of these gear sets is the result of years of racing development, outstanding design, and state-of-the-art manufacturing methods.

Posi LSD

New Clutch type posi differential provides aggressive yet smooth traction, perfect for street and performance applications. These units are fully rebuildable and use Eaton type internal components. We recommend using standard 80/90wt (non-synthetic) oil with posi additive.

4 Spring Clutch type Posi LSD

Nodular Iron Case

4320 Forged Steel Internal Gears

Fully Rebuildable

Assembled in the USA

Master Install Kit

Premium master install kit uses only the highest quality components including Timken brand bearings. Included are carrier bearings and races, pinion bearings and races, pinion seal, complete shim kit, ring gear bolts, pinion nut, crush collar, threadlock, marking compound, brush, and gasket or RTV silicone. 

Application: 1968-1972 Oldsmobile "O" Axle Rearend

1968-1972 Olds Cutlass

1968-1972 Olds 442

Cover bolts: 12

Ring Gear Bolts: 10

Axle splines: 31 (must verify before ordering)

Pinion Splines: 27

Package Includes:

1- GM 8.5" Olds 3.90 Ring & Pinion Set

1- GM 8.5" Olds Posi LSD (31 Spline)

1- GM 8.5" Olds Master Install Kit