Ford 8.8-Inch Rear Axle History & Specs

Usage:

The Ford 8.8-Inch axle came in a few different vehicles including the:

• Ford Mustang (1986-2014)
• Ford Bronco (1983-1996)
• Ford F-150 (1983-2012)
• Ford Ranger (1990-2011 4.0L models)
• Ford Aerostar (1989-1997)
• Ford Explorer (1991-2001) (The Ford Explorer Sport still used the solid rear 8.8 until 2003)

8.8-Inch Axle History:

First Use: Ford began using the 8.8-Inch axle in trucks in 1983.

Ranger Chassis Cabs: Ford began using the 8.8-Inch axle in Rangers around 1986 on ‘incomplete vehicles’ aka ‘chassis cabs’. The 1986-1988 (chassis cab) 8.8-Inch axles are distinctive as they are the only 8.8-Inch Ranger rears that have no provisions for a RABS sensor.

Ranger 4.0L Models: The Ford 8.8-Inch axle began regular use in the Ford Ranger starting with the 1990 4.0L models. All 4.0L Ford Rangers are equipped with 8.8-Inch axles.

1998-2011 Super Cabs: 1998-2011 Ford Ranger super cabs regardless of engine size are frequently equipped with 8.8-Inch axles.

FX4 Models: All Ford Ranger 8.8-Inch axles have 28-spline axle shafts except for the 2002 FX4 and 2003 & newer FX4 Level II models which had 31-spline shafts.

The FX4 Ranger was introduced in 2002 and always came with 4.10 gears only. The 31-spline Torsen 8.8-inch axle came only with the 2002 FX4 and 2003-up FX4 Level II and more recently was a separate option. The 2003-up FX4 (non-Level II) is essentially the same as the 1998-2002 Off-Road except that a regular Ford limited-slip in a regular 8.8-inch was included.

Ford Explorer: The 8.8-Inch axle came in Ford Explorers (and Mazda Navajo) in 1990 as a 1991 model year. The Ford Explorer used it until it switched to an independent rear suspension in 2002. The exception is the 2002-2003 Ford Explorer Sport which still used the solid rear 8.8-Inch axle.

Ford Aerostar: The 8.8-Inch axle was used in 2WD 4.0L Ford Aerostars, but the All-Wheel-Drive (AWD) Ford Aerostar was equipped with the 7.5-Inch axle.

Ford F-150 / Bronco: The Ford F-150 used the Ford 8.8-Inch axle From 1983-2012 except for 5.4L (including Lightning) and some 4×4 super cabs and higher GVWR models which were equipped with the heavier-duty 9.75-Inch rear axle. It was also used in the 1983-1996 full-size Bronco, and E150 Econoline vans.

Ford Car Usage: The 8.8-Inch is also used in other Ford products such as Ford Mustang’s, Ford Thunderbird’s, Ford Crown Victoria’s, and their equivalent Mercury and Lincoln products.

Mustang Note: Mustang owners have been known to take the left axles from 1990-1992 Ford Ranger 8.8-Inch axles to convert their axles from a 4-lug to a 5-lug wheel bolt pattern, or to replace an axleshaft.

Wheel Bolt Pattern: Ford Rangers, Explorers and Mustangs have a 5×4.5 wheel bolt pattern. F-150 and Bronco have a 5×5.5 wheel bolt pattern.

Miscellaneous: A wide range of gear ratios is available, from 3.08’s up to 6.14’s. An equally wide array of differentials is also available from open carriers to limited slips to lockers and spools.

8.8-Inch axles can have either 28-spline or 31-spline axles.

Gear sets are interchangeable between axles, regardless of the spline count. Differentials, however, are not.

Disc Brakes:

• The 1995-2003 Explorer 8.8-Inch axles come with disk brakes.
• The 2010-2011 Ford Ranger rear axles come with disc brakes.
• The 1999-2012 Ford F-150 8.8-Inch axles come with disc brakes.

The axle above in an 8.8-Inch from a 1995+ Ford Explorer. You can quickly identify it as an Explorer axle due to its rear disk brakes and the spring perches mounted below the axle tube instead of on the top. When swapping an Explorer 8.8-Inch axle in to a 4WD Ranger you need move the spring perches to the top of the axle tube.

Axle Shaft Splines:

Ford Mustang – The Ford Mustang 8.8-Inch axle from 1986-2004 used 28-spline shafts. The 2005-2014 Ford Mustang 8.8-Inch axle used 31-spline shafts.

Ford Ranger – The Ford Ranger 8.8-Inch axle used 28-spline shafts.

Ford Ranger FX4 – The 2002 FX4, 2003-2007 FX4 Level II, and 2008-2009 FX4 Off Road models had 31-spline shafts.

Ford F-150 / Bronco – The Ford F-150 and Ford Bronco 8.8-Inch axles had 31-spline shafts.

Ford Aerostar – The Ford Aerostar 8.8-Inch axles had 28-spline shafts.

NOTE: Increasing from a 28-spline to a 31-spline axle allegedly increases strength of the axle shaft by 34%, however I’ll go by the capacity ratings of the axle assemblies provided by the manufacturer. Ford Rates the Ranger axle at 2750 lbs and the Explorer axle at 3200 lbs this is a 16% increase in strength, which admittedly may be as conservative as the estimate of axle strength. The Important thing about the Explorer axle assembly (besides its 31-spline shafts) is that its axles are larger in diameter at the outer bearing journal AND the larger diameter bearings used.

Axle Tube Diameters:

• The 1990-2009 Ford Ranger 28-spline 8.8-Inch axle tube is 2.80 inches in diameter.
• The 2010-2011 Ford Ranger 28-spline 8.8-Inch axle tube is 3.25 inches in diameter.
• The Ford Ranger 31-spline 8.8-Inch axle tube is 3.25 inches in diameter.
• The Ford Explorer 31-spline 8.8-Inch axle tube is 3.25 inches in diameter.
• The Ford F-150 / Bronco 31-spline 8.8-Inch axle tube is 3.25 inches in diameter.
• The Ford Mustang 8.8-Inch Axle tube is 2.80 inches in diameter.

Axle Bearings:

• Ford Ranger 8.8-Inch 28-spline axle bearing ID= 1.399″, OD= 2.25″ (1563 bearing)
  • 2010-2011 28-spline 8.8-Inch axles axles use the larger 1559 bearing below.
• Ford Explorer 8.8-Inch 31-spline axle bearing ID= 1.618″, OD= 2.533″ (1559 bearing)
• Ford F-150 / Bronco 31-spline axle bearing ID= 1.618″, OD= 2.533″ (1559 bearing)

NOTE: The 28-spline 8.8-Inch axle uses the same size axle bearing (at the wheel end of the axle) as the Ford 7.5-Inch axle. Many Ranger owners have purchased new axle bearings only to find out that they were sold the bearing for the larger 31-spline 8.8-Inch axle. The exception is the 2010-2011 Ford Ranger 8.8-Inch rear axle. It uses the larger axle bearing.

Axle Width Differences:

• 1990-1992 Ford Ranger 8.8-Inch Axle – 56.50 inches
• 1993-2009 Ford Ranger 8.8-inch Axle – 58.50 inches
• 2010-2011 Ford Ranger 8.8-Inch Axle – 58.50 inches *
• 1991-2003 Ford Explorer 8.8-Inch Axle – 59.625 inches
• 1989-1997 Ford Aerostar 8.8-Inch Axle – 62.50 inches
• 1983-1996 Ford Bronco 8.8-Inch Axle – 65.125 inches
• 1986-1993 Ford Mustang 8.8-Inch Axle – 59.25 inches
• 1994-2004 Ford Mustang 8.8-Inch Axle – 61.25 inches
• 1989-1999 Ford Crown Victoria 8.8-Inch Axle – 62.50 inches

* The 2010-2011 Ford Ranger 8.8-inch axle is actually narrower and has shorter shafts than the 2009 and earlier models. Ford used rear disc brakes on the 2010-2011 Rangers, so Ford Shortened the axle housing and shafts to compensate for the extra width created by the disc brake setup. These shafts are not going to work in a 2009 and older Ford Ranger 8.8-inch axle.

For more information, check out ‘2010 Ford Ranger 8.8-Inch Axle vs 2004 8.8-Inch Axle‘

Specifications:

Ford 8.8-Inch Axle – Specifications – Ring Gear & Differential
Ring Gear Diameter	8.8 Inch
Ring Gear Bolts	(10) 7/16″ x 20
Differential Cover Bolts	10
Pinion Stem	1.626 Inches
Pinion Splines	30
Pinion Bearing Preload (New)	14-19 in lb
Pinion Bearing Preload (Used)	8-10 in lb
Back Lash	.011″-.016″
Ring Gear Bolt Torque	70-85 ft lb
Bearing Cap Bolt Torque	70-85 ft lb
Fluid Type	Use hypoid gear lubricant SAE 75W80 or 80W90 (Add 2 oz. friction modifier to axles with limited slips)
Fluid Capacity	5 pints (expect to use 2-3 quarts if changing the fluid. More if you have an aftermarket heavy duty cover.
When installing a new ring gear, use the torque specifications recommended by the ring gear manufacturer.

 

Ford 8.8-Inch Axle – Specifications – Axle Shaft
Vehicle	Side / Length	Spline / Diameter	Axle Bearing
1983-1992 Ford Ranger	Right Hand / 26.250 Inch	28-Spline / 1.21 Inch	1563
1983-1992 Ford Ranger	Left Hand / 29.125 Inch	28-Spline / 1.21 Inch	1563
1993-2009 Ford Ranger	Right Hand / 27.250 Inch	28-Spline / 1.21 Inch	1563
1993-2009 Ford Ranger	Left Hand / 30.125 Inch	28-Spline / 1.21 Inch	1563
2010-2011 Ford Ranger	Right Hand / 27.000 Inch	28-Spline / 1.21 Inch	1559
2010-2011 Ford Ranger	Left Hand / 29.9375 Inch	28-Spline / 1.21 Inch	1559
2002-2009 Ford Ranger FX4	Right Hand / 27.250 Inch	31-Spline / 1.32 Inch	1559
2010-2009 Ford Ranger FX4	Left Hand / 30.125 Inch	31-Spline / 1.32 Inch	1559
1995-2002 Ford Explorer	Right Hand / 27.620 Inch	31-Spline / 1.32 Inch	1559
1995-2002 Ford Explorer	Left Hand / 30.500 Inch	31-Spline / 1.32 Inch	1559
All of these 8.8-Inch axles use 1/2-inch wheel studs. All of these 8.8-Inch axles have a 5×4-1/2 (5×4.5) wheel bolt pattern

 

Ford Ranger & Explorer 8.8-Inch Axle Dimensions
	1983-1992 Ford Ranger	1993-2009 Ford Ranger	2010-2011 Ford Ranger W/Discs	Ford Explorer
Width WMS-WMS	56.50 inches	58.50 inches	57.50 inches	59.625 inches
Axle Tube Diameter	2.80-inches	2.80-inches (28-spline) 3.25-inches (31-spline)	3.25-inches	3.25-inches
Pinion Offset Right Of Center	2-inches	2-inches	2-inches	2-inches
Pinion Offset Below Centerline	1.50-inches	1.50-inches	1.50-inches	1.50-inches
Pinion Length (axle centerline to u-joint centerline):	11-5/8 inches	11-5/8 inches	11-5/8 inches	11-5/8 inches
Bottom Of Housing From Centerline	5-3/4 inches	5-3/4 inches	5-3/4 inches	5-3/4 inches
Stock Spring Perch Width	38-1/2 inches	38-1/2 inches	38-1/2 inches	38-1/2 inches
Axle Spline / Diameter	28 / 1.21 inches	28 / 1.21 inches	28 / 1.21 inches	31 / 1.32 inches
Pinion Stem Diameter	1.626 inches	1.626 inches	1.626 inches	1.626 inches
Ring Gear Diameter	8.80 inches	8.80 inches	8.80 inches	8.80 inches
Ford Ranger FX4 with a 31-spline 8.8-Inch axle should have a 1.32-inch diameter axle shaft.

 

Identification From Axle Tag:

The axle tag is bolted to the rear differential cover, and is held on with one of the cover bolts.

From the example above, you can see that the lower line shows the gear ratio, and axle diameter.

So from that example, we can see that the tag above is a 7.5 inch axle with 3.73 gears.

The tag above is a 8.8 inch axle, and also has 3.73 gears, but there is a ‘L’ between the ‘3’ and the ’73’. This means that it is a Limited Slip axle.

The tag above is from a 8.8 inch rear axle in a 2001 Ford Ranger 4×4 super cab with 4.10 gears.

Federal Compliance Sticker:

Another way to identify the axle in a Ford Ranger is from the Federal Compliance Sticker in the door jamb.

If you look at the ‘AXLE’ section on the label above, you’ll see that this Ranger has a ‘F7’ axle code. Using the chart below, we know that this axle is a 7.5-Inch axle with a 4.10 limited slip.

Axle Codes: