Carraro front axle - Problem identification and diagnostics


Problem - Noise when vehicle is moving
Cause - 1. Excessive backlash between the ring gear and pinion.
            2. Ring gear or pinion worn.
            3. Pinion bearings worn.
            4. Pinion bearings loose.
            5. Excessive pinion axial clearance.
            6. Differential bearings worn.
            7. Differential bearings loose.
            8. Excessive ring gear out-of-round.
            9. Hydraulic fluid low.
          10. Insufficient or incorrect grade lubricant.
          11. Stub axle warped.
Action required – 1. Adjust backlash.
                        2. Replace the defective component.
                        3. Replace the bearings.
                        4. Adjust the bearings.
                        5. Adjust backlash.
                        6. Replace the bearings.
                        7. Adjust the bearings.
                        8. Replace the ring gear.
                        9. Top up level.
                       10. Change lubricant.
                       11. Replace the stub axle.

Problem - Noise when engine is in neutral position
Cause - 1. Noises caused by the axle can generally be heard faintly when the engine is in neutral position.
            2. Incorrect backlash between the pinion and ring gear (the noise can be heard at the end of deceleration, when the engine starts to accelerate).
            3. Input flange or pinion excessively worn.
Action required - 1. Adjust or replace.
                        2. Adjust backlash.
                        3. Replace defective parts.

Problem - Intermittent noise
Cause - 1. Ring gear damaged.
            2. Differential unit bolts loose.
Action required - 1. Replace the bevel gear.
                        2. Tighten to the required torque.

Problem - Continuous noise
Cause - 1. Ring gear or pinion damaged.
           2. Bearings worn.
           3. Pinion splines worn.
           4. Stub axle warped.
Action required - 1. Replace the bevel gear.
                        2. Replace the bearings.
                        3. Replace the pinion.
                        4. Replace the stub axle.

Problem - Noise when changing steering angle
Cause - 1. Differential pinion gears worn.
            2. Differential unit and / or spider worn.
            3. Differential thrust washers worn.
            4. Stub axle splines worn.
Action required - 1. Replace the pinion gears.
                        2. Replace defective components.
                        3. Replace the bearings.
                        4. Replace the stub axle.