The Mustang came from the factory with a 7.5-inch or 8.8-inch rear end, after 1979, with a variety of gear ratios and in both limited slip and open differential configurations. Decoding the data tag on the rear end will provide the information required when ordering replacement or up-graded parts for the Ford differential inside the rear end. The average Mustang enthusiast can decode the rear end data tag in just a few minutes.
Things You'll Need
- Wheel chocks
- Floor jack
- Jack stands
- 13-mm wrench
Park the Mustang on level ground and wedge wheel chocks in front of the front tires. Lift the rear of the Mustang using a floor jack under the differential housing. Place jack stands under the Mustang's rear axle tubes and lower the car onto the stands for support.
Slide under the car and clean off any accumulation of grease and dirt with a shop towel. Remove the 13 mm bolt, using a 13 mm wrench, that attaches the data tag to the differential, if the first part of the code on the tag is hidden by the bolt head.
Decode the data tag. The first line of the data is the axle code and may be needed when ordering axles and other rear end parts from the factory. The second line of data indicates the gear ratio, ring gear size, and differential configuration (open or limited slip). For example: A second line of data that reads "3L08 88 ***" would be a gear ratio of 3.08-to-1, a ring gear size of 8.8-inches, and the "L" in the first four digits indicates a limited slip differential. If the space where the "L" is in this example is blank it is an open differential and if the "88" is replaced with a "75" it has a 7.5-inch ring gear size.
- "Chilton 1994-98 Ford Mustang Repair Manual"; George B. Heinrich III, ASE, SAE; 1997
How to Indentify a Ford Truck Axle
Ford truck axles are heavy duty pieces of equipment that come in different sizes and final drive ratios to fit the needs...
How to Identify Ford Rear Ends
Ford rear ends, or differentials, were manufactured by either the Dana Corporation or Ford. Differentials take the power from the rear axle...
How to Find Out the Gear Ratio With the VIN Number
The vehicle identification number (VIN) is a 17-digit code that is used to identify and track every automobile produced. Each number and...
How do I Identify a Ford Differential?
Differentials are the gears housed within the rear end unit of a vehicle, aiding in the transfer of power to the wheels...
How do I Change a Mustang's Gear Oil?
Gear oil is used to fill a vehicle's differential. Ford uses a few different types of differentials, but the standard rear-end is...
How to Tell the Size of My Ford Rear End
If you have a Ford, you can identify the size of the rear end in a matter of minutes. You do not...
How to Remove a Mustang Rear Axle
The rear axle on a Ford Mustang turns the rear wheels. This axle has many different internal components that can be damaged...
How to Read an Axle Identification Tag
Automobile manufacturers place vehicle specification information in a series of numeric and alphanumeric codes on the rear axle near the rear differential....
How to Read a Ford Truck Axle Tag
Ford truck axles are identified by a small tag attached to the differential casing on the rear axle in most cases. The...
How to Decode Ford Doortags
The tag inside the door on all Ford vehicles refers, in an alpha-numeric code, to the vehicle's exterior paint colors, the vehicle's...
1967 Mustang Vehicle Specifications
The year 1967 was important for Ford's Mustang. Facing increasing pressure from other automobile manufacturers, Ford made the 1967 Mustang available with...