Reference Manual

Chapter 3: Axles: Factory Useage

If a rear axle is known to be the original axle installed by the factory and the vehicle has a SPID, a simple method to determine the rear axle ratio would be to lookup the axle RPO.

2.14	G72	2.93	GU3
2.29	GH2	3.08	GU4
2.41	GU1	3.23	GU5
2.56	GM8	3.42	GU6
2.73	GU2	3.73	GT4

Positraction		G80

Without a SPID or if it's possible the axle had been swapped at some point the axle code on axle can be used to determine the axle ratio.

Naturally, this assumes the original gears remain in the original housing.

Code Locations

A manufacturer code will be metal stamped on the axle tube adjacent to the carrier for field identification. This code will be stamped on the right front inboard side, letters and numerals 1/4" high, 3" outboard of carrier and/or are located on a metal tag attached to a cover bolt.

Code Breakdown

A Body Axle Codes	G Body Axle Codes
1978 1979 1980 1981	1982 1983 1984 1985 1986 1987 1988

Table of Contents		Top of Chapter

Copyright © 1998-2024 by The Members of The Oldsmobile Mailing List. All Rights Reserved. This web site is not affiliated with General Motors or Oldsmobile. General Motors and Oldsmobile are trademarks of their respective companies. The owners and members of this site are not responsible for errors or inaccuracies.