GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Tracker - 2WD 🢒 Driveline/Axle 🢒 Front Drive Axle 🢒 Gear Tooth Contact Pattern Inspection

Application Procedure

    Object Number: 205477 Size: SH
  1. Apply a light coating of gear marking compound GM P/N 1052351 (Canadian P/N 10953497), or the equivalent, to the ring gear teeth not making contact with the pinion gear.
  2. Insert a standard drift punch between the ring gear and the differential carrier to bind the ring gear and create a drag.

    3. Important: In order to ensure an accurate contact pattern, make sure the ring gear turns one revolution only.

  3. Slowly and evenly turn the pinion gear in the drive direction until the ring gear has made one complete revolution. Because of the drag simulated in the ring gear, this will produce a contact pattern on the drive side of the ring gear (pinion gear driving ring gear).
  4. Turn the pinion gear in the opposite direction with a drag simulated on the ring gear to produce a contact pattern on the coast side of the ring gear (ring gear driving pinion gear).

Inspection Procedure

    Object Number: 205482 Size: SH
  1. Inspect the drive side (2) of the ring gear teeth (concave) and the coast side (1) of the ring gear teeth (convex).
  2. Inspect the contact pattern around the ring gear (3). Uneven contact around the ring gear indicates excessive ring gear runout.
  3. Inspect the drive pattern. The drive pattern should be centrally located between the top and the bottom of the ring gear teeth. Under an increased load, the pattern spreads out and tends to move toward the heel of the tooth.

    4. Inspect the toe. To compensate for an increased load the contact pattern can be somewhat closer to the toe.

  4. Inspect the heel. Under heavy loading conditions, up hill or rapid acceleration, the pattern may extend almost the full distance between the heel and the toe. Refer to Heel to Toe Patterns.
  5. Inspect the pinion gear for the proper selective shim if excessive contact pattern error is present with the proper backlash specification.

Heel To Toe Patterns
   • 
Object Number: 205408 Size: SH
  • A typical drive pattern from heel (2) to toe (1) has a normal drive contact.
    •    • 
    Object Number: 205439 Size: SH
  • A drive pattern under load from heel (2) to toe (1) has a normal drive contact.
    •    • 
    Object Number: 205444 Size: SH
  • A coast pattern from heel (2) to toe (1) has a normal drive contact.
    •    • 
    Object Number: 205448 Size: SH
  • A ring gear which is too far from the pinion causes the heel (1) contact to move the ring toward the pinion.
    •    • 
    Object Number: 205451 Size: SH
  • A ring gear which is too close to the to the pinion causes the toe (1) contact to move the ring away from the pinion.
    •    • 
    Object Number: 205453 Size: SH
  • A pinion which is too far from the ring gear (1) causes the face contact to move toward the ring.
    •    • 
    Object Number: 205454 Size: SH
  • A pinion which is too close to the ring gear (1) causes the flank contact to move away from the ring.

    • Outer End To Inner End Patterns
       • 
    Object Number: 205456 Size: SH
  • Contact between the outer end and inner end on the drive side and the coast side is normal.
    •    • 
    Object Number: 205459 Size: SH
  • An inner end and outer end high contact is caused by a shallow pinion depth.
    •    • 
  • Increase the pinion selective shim size.
    •    • 
    Object Number: 205461 Size: SH
  • An inner end and outer end low contact is caused by a deep pinion depth.
    •    • 
  • Decrease the pinion selective shim.
    •    • 
    Object Number: 205464 Size: SH
  • Replace the differential carrier if an offset coast and drive pattern occurs.
    •    • 
    Object Number: 205467 Size: SH
  • Inspect the pinion gear for proper seating if an erratic contact patterns exist.
    •    • 
  • Replace the ring and pinion gear set if an erratic contact patterns exist.
    •    • 
  • Replace the differential carrier if an erratic contact patterns exist.
    •    • 
    Object Number: 205468 Size: SH
  • Replace the ring and pinion gear set if an insufficient contact patterns exist.
    •    • 
  • Replace the differential case if an insufficient contact patterns exist.