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Founder, 1929-2014
Speedy Bill
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GM 10 Bolt 7.5 Inch Ring and Pinion

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GM 10 Bolt 7.5 Inch Ring and Pinion

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Q & A

What's in the Box

IMPORTANT NOTE: Ring & Pinion  ratios are designed for use with a "3 series" carrier. If you intend to install these ratios with a "2 series" carrier, you need to use ring gear spacer #910-48305.

  • 7.50" diameter ring gear
  • 1.438" diameter pinion
  • 27 splines


  • 1975-79 Omega
  • 1982-99 Camaro/Firebird
  • 1983-99 S-10/S-15/Astro Van
  • 1976-79 Skylark
  • 1977-90 Fullsize Olds/Buick/Pont
  • 1977-96 Fullsize Chevy
  • 1978-81 Century/Phoenix/Ventura
  • 1978-87 Cutlass/Grand Prix
  • 1978-87 Monte Carlo/Regal


Note: Circle track racing applications require a minimum of 4 qts. of rear end lube.  Using less than this amount will lead to immediate pinion bearing failure.

You may also be interested in:

DVD - Richmond Gear Installation Instruction
(Part #2379334)
                        Shows you how to properly install ring and pinion gear sets. Packed with information for correct installation procedures. 
Richmond 92-0775-2605 Powertrax GM 7.5 10-Bolt Locking Differential
(Part #91028019)

The 7.5 inch Powertrax Traction System is the latest design in traction adding differential technology. It combines the smooth operation of a limited-slip differential, with the traction performance of a locking differential. A precise synchronization mechanism eliminates the ratcheting sounds typical of other locking differentials. Special gear and spring design reduce the backlash and therefore driveline windup. An ultra-strength alloy material is used throughout, which is 67% stronger than titanium.

Installation is simple because no ring and pinion set-up is required. In addition, no special tools or oils are needed (installs in about one hour). Step by step model specific instructions are provided with every kit.

  • Positive traction - full locker
    • Delivers engine power to both wheels when coming off the line
    • Upgrade and improve your times and your vehicles reputation 
  • Smooth quiet operation - fully automatic
  • 7.5 Inch Powertrax Unit
  • Do-it-yourself - installs in about one hour
  • No special tools required
  • Works for both cars and trucks
  • Gives 2-wheel drive trucks the traction power of 4x4's
  • Excellent replacement for Posi trac style lockers
  • No special gear lube required
  • Use 85W-140 in warm climates, 80W-90 in cold climates


Motive Gear R7.5GR GM 7.5 In 10 Bolt Ring Pinion Install Kit-27 Spline
(Part #919831023)
                        Everything you need for a complete ring and pinion installation job. 

Kit Includes:

  • cover gasket
  • crush sleeve
  • marking compound and brush
  • pinion and carrier bearings
  • pinion nut and washer
  • pinion seal
  • thread locking compound
  • sealer
  • side case and pinion bearings
  • pinion crush sleeve
  • seal and pinion nut
  • Also comes with lock tite and pattern marking compound and gasket.

Note: Pinion-depth shims are not included. 

7 1/2 Inch GM Ring Gear Spacer with Bolts
(Part #91048305)

Allows you to install a bigger series gear set onto a smaller series carrier. Precision ground to ensure trueness and provide proper backlash. Fits 7.50" diameter ring gear with 1.438" diameter pinion (27 spline). Longer, LH thread ring gear bolts are included with this spacer.

1977-98 GM 10-Bolt Mini Spool
(Part #91048603)
                        Works on '77-'98 GM 10-bolt rearends with 7.5" ring gear and 26-spline axles. Economical way for all race cars to "lock" the rearend. Will not work in posi rearends.

910-48603 Instructions (PDF)