I guess you are not out today hiding behind a hiway sign..
Look for an exploder with rear disks. The gear ratio on fords is written on the drivers door post.. If you look really hard you can find 4:11's and somewhere there are 4:56's they tell me. The door code has been posted here many times... Something like this:
Ford Ranger Rear Axles



Most Rangers are equipped with the Ford 7.5-inch rear axle with several exceptions:

1) 1986-up "Incomplete vehicles" also known as "Chassis Cabs" were frequently equipped with 8.8" 28-spline axles, the '86-88 examples are distinctive as they are the only 8.8" Ranger rears that have no provisions for a RABS sensor.

2) 1990 & up 4.0-liter Rangers. These are ALWAYS equipped with the 8.8-inch 28-spline rear axle.

3) 1998-up 4x4 supercab Rangers regardless of powerplant are frequently equipped with 8.8" axles

4) FX4 Rangers 99-current come equipped with an 8.8 rear and 31-spline axles with either 4.10 or 4.56 axle ratios.

Swapping in an 8.8-inch 28-spline Ranger axle for the original 7.5-inch axle provides (according to Ford) a 35% increase in strength. But this strength increase refers to the greater strength of the gears and carrier bearings (Pinion bearings, axle bearings and axle shafts are exactly the same) there is NO increase in weight capacity If you are looking for greater strength for loads created by severe offroad driving or towing you'll want to go to the next step, the Explorer axle.

The rear axles on all Ford Explorers are also 8.8's, however there are some differences... The 8.8-inch Explorer axle use 31-spline axle shaft. 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 vis-a-vie it's strength is not the axles that are larger at the splines but that these axles are larger in diameter at the outer bearing journal AND the larger diameter bearings used.

What axle do you have now?

You can identify which axle you have by the tag attached to the inspection
cover.

Some feel better having disc brakes (I'll discuss this elsewhere:) and if you want discs then look for a Explorer '95-01, as these are the ones with the disks brakes. '91-94 axle assemblies are just as strong, but have 10" drums (Which are more easily connected to your existing hydraulic lines and Parking brake cables)





7.5-inch Rear Specifications

7.5-Inch Ring Gear

1.626" Pinion Stem

8.8-inch Rear Specifications

8.8-Inch Ring Gear

1.626" Pinion Stem



Swapping a Ranger 7.5-inch to a Ranger 8.8-inch is a direct replacement. Swapping in a stronger 8.8-inch from an Explorer requires mounting the spring perches from under to over the axle. This should be done by a reputable welder. The '95 & newer Explorer 8.8-inch axles have disk brakes. The master cylinders in the Rangers are not calibrated for rear disk brakes. When converting to rear disks you should replace your master cylinder with one from a rear disk brake Explorer.

C-Clips:

The 7.5-inch and 8.8-inch axles retain the axles using C-Clips. A broken C-Clip axle will slide out of the axle tube. C-Clip eliminators are available which hold the axle in the axle tube.

Ford Part# M-4220-A

Jegs Part# 873-A1092

Axle Girdle:

Serious Off-Roaders should consider installing an Axle Girdle. They Replace the existing inspection cover and provide support to the differential bearing caps. They also increase the fluid capacity.

Ford Part# M-4033-G (8.8-inch)

Ford Part# M-4033-J (7.5-inch)

Jegs Part# 6-9-101-8.8 (8.8-inch)

Ranger Axle Codes:

Rear axle codes can be found on the Safety Standard Certification label attached to the left drivers side door lock post. The code appears as a number or letter/number combination in the 'Axle' column of the label. The axle can also be identified by the tag on the axle differential cover bolt. See the diagram above to learn how to read the tag.

Axle Codes
Axle codes for Ranger, Bronco2, Explorer and Aerostar (included because 4.10 gears and limited slips are more common than you'd expect)

Aerostar
Code
Description
Capacity
Ratio

22
open 7.5"
2950
4.10

23
open 7.5"
2950
3.45

24
open 7.5"
2950
3.73

25
open 8.8"
2950
3.27

29
open 8.8"
2950
3.55

B2
L/S 7.5"
2950
4.10

B4
L/S 7.5"
2950
3.73

B5
L/S 8.8"
2950
3.55

B9
L/S 8.8"
2950
3.55



(Note: Aerostars with axle codes starting with "1" are Spicer/Dana 30 axles with Aluminum housings)

Bronco II
Code
Description
Capacity
Ratio

42
open 7.5"
2640
3.45

44
open 7.5"
2640
3.73

47
open 7.5"
2640
4.10

D2
L/S 7.5"
2640
3.45

D4
L/S 7.5"
2640
3.73

D7
L/S 7.5"
2640
4.10



Ranger
Code
Description
Capacity
Ratio

72
open 6-7/8"
2200
3.08

74
open 6-7/8"
2200
3.45

82
open 7.5"
2750
3.08

84
open 7.5"
2750
3.45

86
open 7.5"
2750
3.73

87
open 7.5"
2750
4.10

91
open 8.8"
2750
3.27

92
open 8.8"
2750
3.08

95
open 8.8"
2750
3.55

96
open 8.8"
2750
3.73

97
open 8.8"
2750
4.10

98
open 8.8"
2750
4.56

F4
L/S 7.5"
2750
3.45

F6
L/S 7.5"
2750
3.73

F7
L/S 7.5"
2750
4.10

R5
L/S 8.8"
2750
3.55

R6
L/S 8.8"
2750
3.73

R7
L/S 8.8"
2750
4.10

R8
L/S 8.8"
2750
4.56



(Note 4.56 geared axles '99-up are 31-spline)

Explorer
Code
Description
Capacity
Ratio

41
Open 8.8"
3200
3.27

43
Open 8.8"
3200
3.08

44
Open 8.8"
3200
3.73

45
Open 8.8"
3200
3.55

D1
L/S 8.8"
3200
3.27

D2
L/S 8.8"
3200
4.10

D4
L/S 8.8"
3200
3.73

D5
L/S 8.8"
3200
3.73


L - Limited Slip Differential
C - Conventional Differential
Code
Ratio

85
3.55C

89 (1992-1998)
4.10C

89 (1999-2001)
4.56C

F5
3.55L

K6 4.10L

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