1. Clean all case/housings in solvent.
2. Inspect for the following conditions:

•	Damaged gasket sealing surfaces (1)

•	A loose, damaged, or restricted vent tube (2)

•	Worn, scored, or loose bearing races or worn bearing race bores (3)

•	Damaged drain plug (5)

•	Damaged fill plug hole threads (4)

•	Damaged bolt threads (6)

•	Damaged oil seal bores (7)

1. Clean the gears and shafts in solvent.
2. The ring gear and pinion must be inspected for proper wear and pattern.

•	The end of the gear tooth farthest away from center of ring gear (1) is the heel end of the tooth.

•	The end of the gear tooth nearest center of ring gear (2) is the toe end of the tooth.

•	The side of the tooth that curves inward or is concave (3) is considered the coast side of the tooth.

•	The side of the tooth that curves outward or is convex (4) is considered the drive side of the tooth.

Inspect the pinion flange seating surface (2) for wear, damaged bolt threads (3) and worn or damaged splines (1).

Inspect the bearing rollers and races for the following conditions:

Inspect bearing rollers and races for heat discoloration. Heat discoloration ranges from a faint yellow to a dark blue color. This discoloration may result from an overload or improper lubrication. Excessive heat causes softening of the rollers and races. Bearing races with a sign of heat discoloration must be replaced.