The contact pattern check is not a substitute for adjusting the pinion depth and backlash. Use this method in order to verify the correct running position of the ring gear and the drive pinion. Gear sets which are not positioned properly may be noisy and/or have a short life. A pattern check ensures the best contact between the ring gear and the drive pinion for low noise and long life.
The side of the ring gear tooth which curves outward, or is convex, is the drive side (4). The concave side is the coast side (3). The end of the tooth nearest the center of the ring gear is the toe end (2). The end of the tooth farthest away from the center is the heel end (1).
The following two adjustments affect the tooth contact pattern:
• | Backlash adjustment |
• | Pinion depth adjustment |
The effects of bearing preloads are not readily apparent on hand-loaded tooth contact pattern tests. However, bearing preloads should be within specifications before proceeding with backlash and pinion depth adjustments.
Adjust the position of the pinion by increasing or decreasing the distance between the pinion head and the centerline of the ring gear. Decreasing the distance moves the pinion closer to the centerline of the ring gear. Increasing the distance moves the pinion farther away from the centerline of the ring gear.
Adjust the backlash by means of moving the side bearing adjuster sleeves which move the case and ring gear assembly closer to or farther from the pinion. Also use the adjuster sleeves in order to set the side bearing preload.
• | If the left side adjuster sleeve is moved in, along with an equal outward movement of the right side adjuster, the backlash will increase. |
• | If the left side adjuster sleeve is moved out, along with an equal inward movement of the right side adjuster, the backlash will decrease. |
Important: Performing the test without loading the gears will not produce a satisfactory pattern.
Important: Avoid turning the ring gear excessively or a poor quality gear pattern impression will result.
Perform the recommended adjustments until the proper pattern is obtained.
The backlash and pinion depth is correct.
None required.
Loose bearing on the drive pinion or in the differential case may cause patterns that vary. If the contact pattern varies, inspect the following preload settings:
• | Total assembly |
• | Differential case |
• | Drive pinion |
If these settings are correct, inspect for damage or incorrectly assembled parts.
The backlash is incorrect. The ring gear is too far away from the drive pinion.
Decrease the backlash. Move the ring gear closer to the drive pinion by adjusting the side bearing adjuster sleeves. Refer to Backlash Inspection and Adjustment .
The backlash is incorrect. The ring gear is too close to the drive pinion.
Increase the backlash. Move the ring gear away from the drive pinion by adjusting the side bearing adjuster sleeves. Refer to Backlash Inspection and Adjustment .
The backlash is incorrect. The ring gear is too far away from the drive pinion.
Decrease the backlash. Move the ring gear closer to the drive pinion by adjusting the side bearing adjuster sleeves. Refer to Backlash Inspection and Adjustment .
The backlash is incorrect. The ring gear is too close to the drive pinion.
Increase the backlash. Move the ring gear away from the drive pinion by adjusting the side bearing adjuster sleeves. Refer to Backlash Inspection and Adjustment .
The pinion depth is incorrect. The pinion gear is too far away from the ring gear.
Increase the pinion depth. Move the pinion gear closer to the ring gear by increasing the pinion shim thickness. Refer to Pinion Depth Adjustment .
The pinion depth is incorrect. The pinion gear is too close to the ring gear.
Decrease the pinion depth. Move the pinion gear away from the ring gear by decreasing the pinion shim thickness. Refer to Pinion Depth Adjustment .