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Differential Identification

Differential and Axle Identification
Accurate Differential Identification is the first and most important step in your differential repair, upgrade or overhaul project. The following information is provided to help you identify the differential you are working on. If in doubt, consult one of our differential experts at (800)510-0950! Professional technical support is available Monday thru Friday from 8am to 5pm Pacific Standard Time.

On this page:  Differential Identification by Tag Number  |  Visual Differential Identification

The most accurate differential identification is provided by the bottom line of the tag number or axle tube stamp. Differential tags can easily be used to identify Dana and Ford differentials.

Differential Identification by Tag Number

Dana Spicer Differential Tags

Dana Spicer Differential Identification Tags

The Bill of Material (BOM) number is used to identify Dana differentials. The BOM will identify the model number, the gear ratio, the type of differential, and all component parts. Traditional BOM’s are 6 digits followed by 1 or 2 digits and start with the numbers 60 or 61. On some tags, the first 2 digits don’t appear on the tag, but they must be used to identify the axle. For instance, you might see 5561-1 for the BOM, but the 60 has been dropped, and one would need to use 605561-1. Later BOM’s may start with the first 3 digits of 200, but these are typically not dropped from the tag.

The BOM may be used with the Dana Expert to identify all aspects of this particular axle. Make sure to select the appropriate Light Duty or Heavy Duty section of The Expert.

Axle Identification

On GM axles made by Dana, the Bill of Material is usually stamped in the right hand tube underneath the spring. These BOM’s normally start with 60, and the first 2 digits are not typically dropped as in some cases with Dana ID tags.

Ford Differential Tags

Ford Differential Identification Tag

Ford differential tags are very straightforward, as indicated above. The Month of Manufacture uses the following format:
A = January, B = February, C = March, etc.


GM RPO Identification Codes


GM Vehicles come with a RPO code tag, usually located in the vehicles glovebox or door jamb. These tags have a wealth of information about your specific vehicle’s equipment and specifications. Read more about GM RPO Axle Identification Codes.



For complete listings of the Differential Parts available for your application, view the West Coast Differentials Catalog located at the top right of this page. We have a huge inventory and orders placed by 4PM Pacific Standard Time can usually ship out the same day!

Need help identifying your differential or not sure which replacement or performance parts you need? Call our staff of differential experts at (800)510-0950. We’re here to help Monday thru Friday from 8AM to 5PM PST.

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Visual Differential Identification

Without an ID tag, differentials are identified by the number of cover bolts, the distinctive shape of the cover, the number of ring gear bolts, and ring gear diameter. They can also be identified by whether the center section is an integral or dropout design. Dropout differentials are also referred to as 3rd members or pumpkins. The chart below shows various differential covers and 3rd Members.

AAM-9.25" Differential

AAM 9.25″ Chrysler Front Differential Cover

Image of American Axle Manufacturing 10.5" Differential Cover

AAM 10.5″ Chrysler Differential Cover

Image of AAM 11.5" GM/Chrysler Differential

AAM 11.5″ GM/Chrysler Differential Cover

Image of AMC-Model-20-Differential Cover

AMC Model 20 Differential Cover

AAM 9.25″ Chrysler Front
AAM 10.5″ Chrysler
AAM 11.5″ GM / Chrysler
AMC Model 20

Image of AMC-Model-35-Differential Cover

AMC Model 35 Differential Cover

Image of Chrysler-7.25"-Differential Cover

Chrysler 7.25″ Differential Cover

Image of Chrysler-8"-IFS Differential Unit

Chrysler 8″ IFS Front Differential

Image of Chrysler-8.25"-Differential Cover

Chrysler 8.25″ Differential Cover

AMC Model 35
Chrysler 7.25″
Chrysler 8″ IFS
Chrysler 8.25″

Image of Chrysler-8.75"-Differential

Chrysler 8.75″ Differential Third Member

Image of Chrysler-9.25"-Differential

Chrysler 9.25″ Differential Cover

Image of Dana-28-Differential Housing

Dana 28 IFS Differential Housing

Image of Dana-30-Differential

Dana 30 Differential Cover Image

Chrysler 8.75″
Chrysler 9.25″
Dana 28
Dana 30

Image of Dana-44-Differential Cover

Dana 44 Differential Cover

Image of Dana-50-Differential Cover

Dana 50 Differential Cover

Image of Dana-60-Differential Cover

Dana 60 Differential Cover

Image of Dana-70-Differential Cover

Dana 70 Differential Cover

Dana 44
Dana 50
Dana 60
Dana 70

Image of Dana-80-Differential Cover

Dana 80 Differential Cover

Image of Dana-S110-Third-Member

Dana S110 Third Member

Image of Ford-7.5"-Differential Cover

Ford 7.5″ Differential Cover

Image of Ford-8"-3rd-Member-Differential

Ford 8″ Third Member

Dana 80
Dana S110
Ford 7.5″
Ford 8″ 3rd Member

Image of Ford-8.8"-Differential Cover

Ford 8.8″ Differential Cover

Image of Ford-9-3rd-Member-Differential

Ford 9″ Third Member

Image of Ford-9.75"-Differential Cover

Ford 9.75″ Differential Cover

Omage of Ford-10.25"-10.5"-Differential Cover

Ford 10.25″ & 10.5″ Cover

Ford 8.8″
Ford 9″ Third Member
Ford 9.75″
Ford 10.25″ & 10.5″

Image of GM-55-Passenger-Differential

GM ’55 Passenger Third Member

Image of GM-55-Truck-Differential

GM ’55 Truck Third Member Dropout

Image of GM-7.25"-IFS-Differential

GM 7.25″ IFS Clamshell Differential

Image of GM-7.5"-Differential

GM 7.5″ & 7.625″ Differential Cover

GM ’55 Passenger
GM ’55 Truck
GM 7.25″ IFS
GM 7.5″ / 7.625″

Image of GM-8"-Differential

GM 8″ Differential Cover

Image of GM-8.2"-Differential

GM 8.2″ Differential Cover

Image of GM-8-2-Buick Olds Pontiac-Differential

GM 8.2″ B.O.P. Cover


GM 8.25″ IFS Differential

GM 8″
GM 8.2″
GM 8.2″ B.O.P.
GM 8.25″ IFS

Image of GM-8.5"-Differential

GM 8.5″ Differential Cover Image

Image of GM-8.6"-Differential

GM 8.6″ Differential Cover Image

Image of GM-12-Bolt-Passenger-Differential Cover

GM 12 Bolt Passenger Differential Cover

Image of GM-12-Bolt-Truck-Differential Cover

GM 12 Bolt Truck Differential Cover

GM 8.5″
GM 8.6″
GM 12 Bolt Passenger (8.875″)
GM 12 Bolt Truck (8.875″)

Image of GM-9.25-IFS-Clamshell Differential

GM 9.25″ IFS Clamshell Differential

Image of GM-9.5"-14-Bolt-Differential

GM 9.5″ Differential Cover Image

Image of GM-10.5"-14-Bolt-Differential

GM 10.5″ 14-Bolt Differential Cover

Image of Toyota-Landcruiser-Differential

Toyota Landcruiser Differential Cover

GM 9.25″ IFS
GM 9.5″
GM 10.5″ 14 Bolt
Toyota Landcruiser

Image of Toyota-7-5"-Early-Dropout-Differential

Toyota 7.5″ Early 3rd Member Differential


Toyota 8″ 3rd Member Differential


Toyota Landcruiser 8″ 3rd Member Differential

Image of Toyota-Landcruiser-9.5" 3rd-Member-Differential

Toyota Landcruiser 9.5″ 3rd Member Differential

Toyota 7.5″
Toyota 8″
Toyota Landcruiser 8″
Toyota Landcruiser 9.5″

Image of Toyota-7.5"-IFS-Front-Clamshell-Differential

Toyota 7.5″ IFS Front Clamshell Differential

Image of Toyota-3rd-Member Tacoma T100

Toyota Tacoma/T100 8″ 3rd Member

Image of Toyota-Landcruiser-8"-Reverse-IFS-Front-Differential

Toyota Landcruiser 8″ Reverse IFS Front

Image of Toyota-Tundra-8-75-Front-Differential

Toyota Tundra 8.75″ IFS Front Differential

Toyota 7.5″ IFS Front Clamshell
Toyota 8″ Rear Tacoma / T100
Toyota Landcruiser 8″ Reverse IFS
Toyota Landcruiser 8.75″ Reverse IFS

Differential Component Identification:For exploded view diagrams with part names, consult page 7 of our catalog (available at the top right of this page)Back to Top

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  • Rancho Cordova, CA 95742
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  • Fax: 916-635-1105

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