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.
Differential Identification by Tag Number
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.
Dana Spicer Differential Tags
Dana Spicer B.O.M. Numbers
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.
Ford Differential Tags
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
Not sure what the part you need is called? Use our Exploded View Diagrams to identify the part by name. This way we’ll be on the same page when you call!
Technical & Sales Assistance
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
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.
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Need your parts ASAP?
For the fastest service, call our Differential Parts Experts at (800) 510-0950 for immediate assistance. We are available to help Monday thru Friday from 8 AM to 5 PM Pacific Standard Time, and most orders placed by 4 PM ship out the SAME DAY!
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