Ford 8.8" Axle

Ford 8.8" Axle

Ford 8.8" rear axle facts, specifications, and part numbers. Fords 8.8 axle is found under many vehicles and has a lot of useful features among its various configurations. The most desirable configuration can be found on 2nd generation (95-2001) Explorers as they can be found with 3.73 and 4.10 gear ratios, factory limited slip, and disc breaks. Unless otherwise specified, this page focuses on Explorer 8.8s.

Check FourWheeler.com for a guide on how to build up a Ford 8.8 axle.

SPECIFICATIONS:

Ford Explorer 8.8 Factory Numbers:

  • Weight (complete assembly): 174 lbs
  • 31 Spline Axle
  • 1.32" Axle Diameter
  • 3.25" Axle Tube Diameter
  • 8.8" Ring Gear Diameter
  • Traction Device - (optional/trac-lock)
  • Disc Brakes (95 and later)
  • Capacity: 6,500 lbs
  • Assembly Length 59 3/4"
  • Driver Shaft Length: 30-5/8"
  • Passenger Shaft Length: 27-3/4"
  • Bolt Pattern: 5 lug 4.5"
  • Gear Oil: 75-140W
  • Fluid levels: 1994 & earlier 5.3 pt (2.65 qt, 2.5L); 1995 & later 5.8 pt (3 qt, 2.8L)

Axle Code Ratio:

  • 41 Open 3.27
  • 42 Open 4.10
  • 43 Open 3.08
  • 45 Open 3.55
  • 46 Open 3.73
  • D4 Limited Slip 3.73
  • D2 Limited Slip 4.10
  • L73 Limited Slip 3.73
  • L - Limited Slip
  • C - Conventional (open)

Axle Shaft Strength by Warn Ind:

  • D35 - 4,300 lb·ft (5830 N·m)
  • D44 - 5,000 lb·ft (6780 N·m)
  • F8.8 - 6,500 lb·ft (8800 N·m)
C: Continuous output torque
M: Maximum output torque
  • Dana 35 rear   870 C; 3480 Max
  • Dana 44 rear 1100 C; 4460 Max
  • Ford 8.8 28s 1250 C; 4600 Max
  • Ford 8.8 31s 1360 C; 5100 Max
  • Dana 60 rear 1500 C; 5500 Max

Assembly:

  • Cover Bolts 28-38 lb·ft
  • Pinion Brg. Preload New 16-29 lb·in
  • Pinion Brg. Preload Used 8-14 lb·in
  • Ring Gear Backlash .008-.015"
  • Ring Gear Bolt to case 70-85 lb·ft
  • Side Brg. Caps 70-85 lb·ft

APPLICATIONS:

The 8.8 is found under a wide range of vehicles. Check your local scrapyard for these models:

  • 1986-2014 Mustang
  • 1982-2012 F-150
  • 1982-1996 Bronco
  • 1991-2011 Ranger 4.0 and select 3.0 engines.
  • 1991-2001 Explorer (Solid)
  • 2001-2010 Explorer (Independent)

References:

IMAGE: Ford 8.8" differential, ring gear and carrier

Upgrades & Modifications:

  • Lockers: 

    • ARB, Eaton, Auburn Pro, Lockright, Trac Lok, Truetrac, OX Lockers. Any locker that replaces the stock carrier will shore up one of the few weak points of this axle.

  • Gear Ratios:

    • Factory ratio options cap out at 4.10, but lower gears (numerically larger) are available up to 5.14:1 from aftermarket providers.

  • Axle Shafts:

    • The stock shafts are typically 1040 or 1050 AISI steel. For increased strength, look for axles in the chromoly group, such as 4340 or Hy-Tuf shafts. Additives such as, silicon, nickel, and molybdenum make them over twice as strong as OEM 1040 steel shafts. Keep in mind, strengthening one part of the drivetrain moves the weak link in the system to another part. Just because the upgraded axle shaft can take extreme shock does not mean your stock differential carrier, drive shaft or transmission is up to the task.

  • Brakes:

    • '95 and up Explorers are equipped with single-piston disc brakes on 12" rotors. Late model V8 explorers will have larger rear pads. Kits to replace the stock rotors or drums with slotted and grooved rotors are available in the aftermarket.

  • Budget Lift:

    • Explorer applications come in a spring-under-axle configuration. This means that the rear leaf packs are mounted below the axle tube. The axle can be modified to a spring-over configuration by welding new spring perches to the top of the axle. This will increase the lift of the rear end by ~5 inches depending on the condition of the rear leafs. Other vehicles that come from the factory with a spring over configuration, such as the Ford Ranger or Jeep XJ, will require a spring over axle (SOA) kit to be installed on the Explorer 8.8.