What ratio is the Ford 8.8 final drive?
The Ford 8.8 final drive ratio is a key specification for the rear differential in many Ford vehicles. The final drive ratio determines the relationship between the rotational speed of the driveshaft and the rotational speed of the rear wheels, which affects the vehicle's acceleration, top speed, and fuel efficiency.
What is the Ford 8.8 Final Drive Ratio?
The Ford 8.8 final drive ratio refers to the gear reduction in the rear differential of Ford vehicles equipped with the 8.8-inch rear axle. Specifically, the 8.8 ratio means that for every one revolution of the driveshaft, the rear wheels will rotate 8.8 times. This is a common final drive ratio used in many Ford trucks, SUVs, and performance cars.
Understanding Final Drive Ratios
The final drive ratio is the last gear reduction in a vehicle's drivetrain, occurring in the rear differential. It determines the relationship between the rotational speed of the driveshaft and the rotational speed of the rear wheels. A higher final drive ratio, like the 8.8 in Ford vehicles, means the rear wheels will rotate slower than the driveshaft, providing more torque to the wheels for acceleration but reducing top speed.
Conversely, a lower final drive ratio will result in the rear wheels rotating faster than the driveshaft, sacrificing low-end torque for higher top speeds. The optimal final drive ratio depends on the intended use of the vehicle, balancing performance, fuel efficiency, and other factors.
Advantages of the Ford 8.8 Final Drive
The Ford 8.8 final drive ratio offers several advantages:
- Improved Acceleration: The 8.8 ratio provides a higher gear reduction, resulting in more torque delivered to the rear wheels for quicker acceleration from a stop.
- Towing and Hauling Capability: The extra torque makes the 8.8 well-suited for vehicles used for towing or hauling heavy loads.
- Durability: The 8.8-inch rear axle housing is known for its strength and reliability, making it a popular choice for high-performance and off-road applications.
However, the higher final drive ratio also results in lower top speeds and slightly reduced fuel efficiency compared to lower ratios.
What is the best gear ratio for Foxbody?
For this reason, the minimum gear most enthusiasts would recommend for an automatic is 3.73:1. In fact, the majority go one step further and bump up to 4.10:1 with very exhilarating results. Word on the street has it that naturally aspirated manual cars are best off using either a 3.55:1 or 3.73:1 gear ratio.
What did the Ford 8.8 rear end come in?
The Ford 8.8 rear end is found in a wide range of Ford vehicles, most commonly in the Ford Mustang (1986-2014), Ford F-150 (1983-2014, with some exceptions), Ford Bronco (1983-1996), and various Ford Panther platform vehicles like the Crown Victoria and Grand Marquis (1985-2011). It is also used in the Ford Explorer (solid axle models, 1991-2001) and Ford Ranger (4.0L models, 1991-2011), among others.
Popular vehicle applications
- Ford Mustang: 1986-2014
- Ford F-150: 1983-2014 (some models, like certain 4x4s and Super Cabs, may have the 9.75" rear)
- Ford Bronco: 1983-1996
- Ford Panther platform: 1985-2011 (including Crown Victoria, Grand Marquis, and Town Car)
- Ford Explorer: 1991-2001 (solid axle models)
- Ford Ranger: 1991-2011 (specifically 4.0L V6 models)
- Ford Expedition: 1997-2003
- Ford Aerostar: 1986-1997 (2WD models with the 4.0L V6)
Other vehicles
- Ford Explorer Sport Trac: 2001-2005
- Mercury Cougar: 1988-1996
- Ford Thunderbird: 1987-1995
- Ford E150/E250 vans: 1983-2006/1998 respectively
- Lincoln Navigator: 1998-2006
Important notes
- Variations exist: There are many variations of the 8.8 axle, differing in width, spline count (28 or 31), and mounting points.
- ID tag: The identification tag on the axle can provide specific details about the gear ratio, style, and whether it has a limited-slip differential.
How many teeth are on a 4.88 ring gear?
39
Description
| Brand | Spicer |
|---|---|
| Gear Ratio | 4.88 |
| Ring Teeth Count | 39 |
| Pinion Gear Tooth Quantity | 8 |
| Ring Gear Diameter (In.) | 9.750 |
How do you tell if you have 3.73 or 4.10 gears?
You can tell if you have 3.73 or 4.10 gears by manually counting, checking the differential cover for a tag, or finding the ratio stamped on the ring gear. The most direct method is to lift the rear wheels, rotate one tire one full revolution, and count how many times the driveshaft turns; 3.75 turns indicates 3.73 gears, while slightly over 4 turns indicates 4.10 gears.
This video demonstrates how to check your gear ratio by counting the driveshaft turns: 48sBent Motorsports OffroadYouTube · Sep 22, 2023
Method 1: Manual count (with the vehicle jacked up)
- Jack up the vehicle: Safely lift the rear of your vehicle and secure it on jack stands. Ensure the wheels are off the ground.
- Mark the driveshaft and a tire: Place a mark on one of the rear tires and a corresponding mark on the driveshaft.
- Rotate the tire: Rotate the marked tire forward one full revolution. For an open differential, you may need to lift only one wheel and have someone hold the other stationary, or lift both wheels and rotate one tire twice while the other tire is on the ground. For a locked differential, lift both rear wheels and have one tire rotate once while the other rotates once in the opposite direction.
- Count the driveshaft turns: Count how many times the mark on the driveshaft has rotated.
- 3.73 gears: The driveshaft will turn approximately 3.753.753.75 times for one full tire revolution.
- 4.10 gears: The driveshaft will turn a little over 444 times for one full tire revolution.
Method 2: Check the differential cover tag
- Locate the tag: Look for a small metal tag that is usually bolted to the differential cover. It may be on one of the bolts.
- Read the ratio: If the tag is still present, the gear ratio will be stamped on it. It will likely be a number like "3.73" or "4.10".
You can watch this video to learn how to find the differential cover tag: 51sFlawed OffroadYouTube · Apr 18, 2022
Method 3: Read the ring gear stamps
- Locate the ring gear: This requires removing the differential cover to get a clear view of the ring gear.
- Find the numbers: Look for two numbers stamped on the teeth of the ring gear, such as "41" and "11".
- Divide the numbers: Divide the larger number (teeth on the ring gear) by the smaller number (teeth on the pinion gear).
- 41÷11≈3.7341 divided by 11 is approximately equal to 3.7341÷11≈3.73
- 41÷10=4.1041 divided by 10 equals 4.1041÷10=4.10
This video shows how to read the ring gear stamps to find the gear ratio: 46sJL LIFE OFFROADYouTube · Nov 18, 2022
