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The Ford 8.8-Inch Solid Rear Axle

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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 4x4 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 5x4.5 wheel bolt pattern. F-150 and Bronco have a 5x5.5 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.

Ford Ranger 8.8-Inch Axle Versus Ford Explorer 8.8-Inch Axle

All 8.8-Inch Ford Explorer axles use 31-spline axle shafts. All 8.8-Inch Ford Ranger axles use 28-spline axle shafts (except FX4 and FX4 Level II which use 31-splines).

The Ford Ranger 28-spline 8.8-Inch axle tube is 2.80 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.

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 2750lbs and the Explorer axle at 3200lbs 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 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.

Disc Brakes:

The 1995-2003 Explorer 8.8-Inch axles come with disk brakes. This is the ultimate stock axle upgrade for your Ranger.

The 2010-2011 Ford Ranger rear 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 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

* 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 Ranger 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.

 

Ford 8.8-Inch Axle - Specifications - Axle Shaft

Vehicle Side Spline Diameter Length Bolt Circle Stud Size Bearing
1983-1992 Ford Ranger Right Hand 28-Spline 1.21 Inch 26.250 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1563
1983-1992 Ford Ranger Left Hand 28-Spline 1.21 Inch 29.125 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1563
1993-2009 Ford Ranger Right Hand 28-Spline 1.21 Inch 27.250 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1563
1993-2009 Ford Ranger Left Hand 28-Spline 1.21 Inch 30.125 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1563
2010-2011 Ford Ranger Right Hand 28-Spline 1.21 Inch 27.000 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1559
2010-2011 Ford Ranger Left Hand 28-Spline 1.21 Inch 29.9375 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1559
2003-2009 Ford Ranger FX4 Right Hand 31-Spline 1.32 Inch 27.250 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1559
2003-2009 Ford Ranger FX4 Left Hand 31-Spline 1.32 Inch 30.125 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1559
1995-2002 Ford Explorer Right Hand 31-Spline 1.32 Inch 27.620 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1559
1995-2002 Ford Explorer Left Hand 31-Spline 1.32 Inch 30.500 Inch 5 x 4-1/2 Inch 1/2 Inch Press 1559

 

Axle Dimensions
 
Ranger 1983-1992
7.5-Inch Axle
Ranger 1983-1992
8.8-Inch Axle
Ranger 1993-2009
7.5-Inch Axle
Ranger 1993-2009
8.8-Inch Axle

Bronco II 1984-1990

7.5 Inch Axle (1)

Ranger 2010-2011
7.5-Inch Axle
With Disc brakes (2)
Ranger 2010-2011
8.8-Inch Axle
With Disc Brakes
Explorer 8.8
Width WMS-WMS 56-1/2 inches 56-1/2 inches 58-1/2 inches 58-1/2 inches 58 inches 58 inches 58 inches 59-1/2 inches
Axle tube diameter (1983-2009 models): 2.80 inches 2.80 inches 2.80 inches 2.80 inches 2.80 inches 3.25 inches 3.25 inches 3.25 inches
Pinion Offset Right Of Center unk 2 inches unk 2 inches 1-1/4 Inches unk 2 inches 2 inches
Pinion Offset Below Centerline unk 1.50 inches unk 1.50 inches unk unk 1.50 inches 1.5 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 11-5/8 inches 11-5/8 inches 11-5/8 inches 11-5/8 inches
Bottom Of Housing From Centerline 5-inches 5-3/4 inches 5 inches 5-3/4 inches 5 inches 5 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 40-1/2 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 28 / 1.21 inches 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 1.626 inches 1.626 inches 1.626 inches 1.626 inches
Ring Gear Diameter 7.50 inches 8.80 inches 7.50 inches 8.80 inches 7.50 inches 7.50 inches 8.80 inches 8.80 inches
(1) The Bronco II 7.5 inch rear axle is ~1-5/8 inches wider than the Ranger 7.5 inch axle. All the additional width is in the passenger side.

(2) The 2010-2011 Ford Ranger 8.8-Inch axle has shorter axle shafts than the 1993-2009 models. Ford narrowed this axle when they switched to rear disc brakes so that the axle would still have the same WMS-WMS width (track width).

 Identifying Your Axle:

You can identify which axle you have by the tag attached to the inspection cover.  
 
Here is an example of an axle tag:

 

 

Looking at that tag, you can see the gear ratio stamped on the lower left, and the axle size (ring gear diameter) stamped in the bottom middle.

So looking at the axle tag above, you can see it's a 3.73 gear ratio with a limited slip in a 8.8 inch axle.

Axle Codes:

The Ford 8.8-Inch axle can also be identified by the sicker on the drivers door. Check out our Ford 7.5 & 8.8 Inch Axle Code page for a break down of codes.

Ford Explorer 8.8-Inch Axle Swap:

Interested in swapping the Ford Explorer 31-spline 8.8-Inch axle in to your Ford Ranger? Check out our Ford Explorer 8.8-Inch Axle Swap page.

 

 

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