Front Differential Assembly: Inspection

Repair or replace the differential gear in the following cases:

• The hypoid drive gear and drive pinion shaft tooth surface are damaged, excessively worn, or seized.
• The roller bearing on the drive pinion shaft has a worn or damaged roller path.
• There is damage, wear, or seizure of the differential bevel pinion, differential bevel gear, washer, pinion shaft, and straight pin.
• The differential case has worn or damaged sliding surfaces.
  Fig 1: Identifying Differential Gear Components

  

1. BEVEL PINION GEAR BACKLASH 

   Measure backlash between bevel gear and pinion. If it is not within specifications, install a suitable washer to adjust it.

   NOTE: Be sure the pinion gear tooth contacts adjacent gear teeth during measurement.

   ST1 498247001 MAGNET BASE

   ST2 498247100 DIAL GAUGE

   Standard backlash:  0.13-0.18 mm (0.0051-0.0071 in)

   Fig 2: Measuring Backlash Between Bevel Gear And Pinion

   
2. HYPOID GEAR BACKLASH 

   Set ST1 and ST2. Insert the needle through transmission oil drain plug hole so that the needle comes in contact with the tooth surface at a right angle and check the backlash.

   ST1 498247001 MAGNET BASE

   ST2 498247100 DIAL GAUGE

   ST3 498255400 PLATE

   Backlash:  0.13-0.18 mm (0.0051-0.0071 in)

   Fig 3: Measuring Hypoid Gear Backlash Through Transmission Oil Drain Plug Hole

   
   NOTE: If backlash is outside specified range, adjust it by turning holder in right side case.
3. TOOTH CONTACT OF HYPOID GEAR 

   Check tooth contact of hypoid gear as follows: Apply a uniform thin coat of red lead on both tooth surfaces of 3 or 4 teeth of the hypoid gear. Move the hypoid gear back and forth by turning the transmission main shaft until a definite contact pattern is developed on hypoid gear, and judge whether face contact is correct. If it is incorrect, make the following correction.

   • Tooth contact is correct.
     Fig 4: Checking Tooth Contact Of Hypoid Gear (Correct Contact Shown)