How Do I Determine Gear Ratio on a Dana 44?

Determining the gear ratio of a Dana-44 equipped vehicle is vital to understanding that vehicle's performance characteristics. Once you know the current gear ratio, you can change it to better suit the intended use of the vehicle. The gear ratio is also useful for determining final tire diameter in custom built projects, as well as anticipating the relationship between engine rpm and vehicle speed. Dana 44 differentials were built with gear ratios from 2.87:1 to 5.89:1. The 2.87:1 ratio is considered a tall gearing, while a 5.89:1 is a very low gearing.

Things You'll Need

• Vehicle
• Jack
• Jack stands
• Socket set
• Drain pan
• New differential gasket
• Differential fluid
• Calculator

Instructions

1. Block the front wheels of the vehicle. Raise the rear of the vehicle with the jack and support it with the jack stands.

2. Locate the differential housing. Remove the drain plug from the bottom of the differential housing and allow the differential fluid to drain completely. On vehicles without a drain plug, the oil will drain when the differential cover is removed. Remove the cover.

3. Examine the ring and pinion gears found inside the differential housing. Count the number of teeth on the largest gear. This is the ring gear. Divide this number by the number of teeth on the small gear. This is the pinion gear. The resulting number is your gear ratio.

4. Replace the differential cover using a new gasket and add new differential fluid. The fill hole is located in the differential cover.

5. Carefully lower the vehicle and check for any fluid leaks.

Tips & Warnings

• Have everything needed to complete the process before beginning.

• Dana 44 differentials are typically found on trucks and 4x4 vehicles, and since these vehicles usually sit higher, it may not be necessary to raise the vehicle to remove the differential cover.

• Always exercise caution when working under a vehicle (ensure it is supported properly).

• Wear eye protection to keep dirt and other debris away from your eyes.