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
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|
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.
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.