SCG Classic Car Troubleshooting Checklist - Rear Axles (Non-Locking Differential)

Ring and pinion gears must be adjusted to mate together within very close tolerances. Otherwise problems arise that include noise, premature wear and vibration. As the gears wear naturally, various symptoms may appear. These symptoms may only appear during certain driving conditions, described as follows:

Drive:
The condition wherein the engine is gradually increasing power and the car is accelerating slowly.

Cruise:
The car's speed is held at a specific level, with neither added engine power nor deceleration.

Coast:
The car's engine is being driven by the mass of the car as it slows down. Maximum engine braking occurs during this phase.

Float:
This is the condition wherein the car gradually slows down, but the engine is producing just enough power to prevent the car itself from dragging (engine braking).

Noise During Acceleration
This noise is almost always due to a too-close heel contact on the ring gear.

Coasting Noise
This noise is due to too-close toe contact on the ring gear.

Noise During All Conditions

1. Ring and pinion assembly bearings worn or defective
2. The ring and pinion gears are worn, either through use or incorrect settings.
3. Differential gear cluster worn due to high mileage.

1. Universal joints are worn or loose.
2. Drive shaft is out of balance
3. Drive shaft center bearing (if fitted) worn or misaligned.
4. Spline in transmission output worn
5. Drive shaft angle incorrect.

1. Universal joints worn.
2. Axle shaft nut loose at differential case.
3. Axle shaft splines worn badly through use.
4. Excessive ring and pinion gear play (tolerance).
5. Worn differential bearings.