Front Differential

GM 7.2

Years Used on Astro / Safari Van: (1990 - 2005)

10 bolt front cover with 7.2" reverse cut ring gear.

The front differential in All Wheel Drive Astro/Safari vans is an independent front suspension design that shares many traits with those found in other GM compact and mid-size trucks.

Front Differential

GM 7.2

Astro / Safari Van: 1990 - 2005

Envoy: 2002 - 2005

S10 Blazer & Pickup: 1983 - 2002

Syclone: 1991 - 1991

Trailblazer: 2002 - 2005

Typhoon: 1992 - 1993

Differential Lockers

Lock-Right locker PT 1935

Differnetial Gears

3.08

3.42

3.73 all S10 ZR2 / Sonoma Highrider 1994-2005

4.11

4.56

Differential Internals

Image credit: Parts.com

Axle Seal Replacement

With the wheels on the ground unbolt the sway bar links (rusted ones may break)

Using solid points on the sub-frame, put the van on jack stands

Remove the wheel

Pull the brake caliper off the and hang from the upper A arm

Remove the rotor

Remove the bolt from the upper ball joint that holds the ABS wire

Dislodge the ABS wire from it's clips

Disconnect the outer tie rod from the steering knuckle (tie rod separator)

Disconnect the upper ball joint from the steering knuckle (sometimes a good wack with a hammer on the side of the knuckle, sometimes a pickle fork, try not to tear the boot)

Disconnect the lower shock mount

Let the lower A arm drop taking care not to let it hang by the ABS wire

Unbolt (1990-1996) or dislodge (1997-2005) the inner CV from the diff

Remove the axle shafts from the diff (crowbar behind CV mount surface (1990-1996) or crowbar placed in the outer clip groove (1997-2005), wiggle/pry out till it pops out)

Remove the old seals (2/3 jaw internal bearing puller with slide hammer)

Install new seals (bearing seal press, extra long handle made out of a 2x4 or similar helps)

Clean/smooth where the seal rides on the axle shaft (1990-1996) or CV (1997-2005)

Reverse to reassemble

Limited Slip & Locking Differentials

Front Differential

Limited Slip

  • MFactory - helical type
  • Bully Racing LLC - helical type

Locking

  • Powertrax

Upgrade Research

GM 8.25

Aluminum front housing found in GM vehicles.

Uses 8.25" reverse cut ring gear