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Ford 8.8 Rear Axle from 1997 Explorer with SOA kit.

Brass tacks, Ford puts these in everything. If you are junkyard diving for an 8.8, here is the one you want:

Rear end out of a 1995-2001 Ford Explorer or Mercury Mountaineer. This version of the 8.8 comes with disc brakes, limited slip carriers, 1.32” – 31 spline shafts, and an 8.8” ring gear with ratios from 3.08 to 4.10 (Aftermarket from 2.26 to 5.71). As of 2016, most junkyards charge ~$200 for the entire assembly, including disc brakes! First gen Explorers (1990-1994) have the same axle codes, but come with drums.

Specs and Measurements:

Weight (complete assembly): 174 lb

Width (overall): 59.5″

Tube OD: 3.25”

Tube Wall: 0.250”

Axle Shafts: 1.625” // 31 spline

Lug Pattern: 5-4.5

Ring Gear Diameter: 8.8”

Ring Gear Bolts: 7/16” x10 // 70-85 ft.lbs

Ring Gear Backlash: 0.008″-0.015″

Pinion Diameter: 1.625” / 30 spline

P. Bearing Preload: 16-29 in.lbs (new)

P. Bearing Preload: 8-14 in.lbs (used)

Cover Bolts: 12mm x10 // 28-38 ft.lbs

Side Bearing Caps: 5/8″ // 70-85 ft.lbs

ABS Sensor hole: 0.811”

Driveshaft Flange: 12 x 1.75 x 30mm // 70-95 lb-ft

Axle Codes:

CODE CARRIER RATIO
41 OPEN 3.27
42 OPEN 4.10
43 OPEN 3.08
45 OPEN 3.55
46 OPEN 3.37
D1 LIMITED SLIP(L) 3.27
D2 LIMITED SLIP(L) 4.10
D4 LIMITED SLIP(L) 3.73
D5 LIMITED SLIP(L) 3.55

How Strong is the Ford 8.8?

The Ford 8.8 is a stout axle. The 31-spline option that ships with early-model Explorers is just shy of equaling a Dana 60, with Super 8.8 kits exceeding the Dana 60. Jeepers looking to upgrade to a Ford 8.8 will enjoy a 47% improvement in strength over their Dana 35 rear ends.

Fourwheeler strength report:

(COT: Continuous output torque rating lb. ft.)

(MOT: Maximum output torque rating lb. ft.)

Dana 35 Rear COT: 870 MOT: 3480
Dana 44 Rear COT: 1100 MOT: 4460
Ford 8.8 (28 spline) COT: 1250 MOT: 4600
Ford 8.8 (31 spline) COT: 1360 MOT: 5100
Dana 60 COT: 1500 MOT: 5500

Full List: Fourwheeler.com

Ford 8.8 Weaknesses

Riveted Axle Tubes. The Ford factory design has the axle tubes riveted to the differential housing with three rivets each. Under high stress (such as oh, I don’t know…jumping your rig 20 feet in the desert) these rivets can crack and cause all sorts of problems.

Solution: Weld those tubes! We used a pair of heat guns and a tiny 110V home MIG welder to add a bit of strength where the tubes meet the housing.

C-clip axles shafts. Disc brake versions don’t have to worry that much, but models with drum brakes should consider a c-clip eliminator kit. The c-clips can sometimes fall out under stress and send your wheel and axle walking the wrong way down the trail! Disc brakes are a buffer against this happening, as the calipers will be able to hold the axle in during normal driving should the c-clip fall out. It should be noted that this is a rare issue, but still one to be considered.

Solution: A c-clip eliminator kit (bought as part of a Super 8.8 kit). This can be expensive however and the chances of your c-clips going AWOL are slim.

Summary

8.8 is the new 9. Its size makes it a perfect fit for hot rods and medium sized 4×4 rigs alike. There is tremendous aftermarket support and the axles can be found with disc brakes, low gearing, and traction devices on the cheap.

Further Reading:

TRS 8.8-Inch Solid Rear Axle

Four Wheeler Axle Tech 101

Explorerforum