TM  10-3930-643-34 FRONT AND REAR AXLES TROUBLESHOOTING  AND MAINTENANCE.  (cont) 7-1. Front  and  Rear  Axles  Troubleshooting. MALFUNCTION TEST  OR  INSPECTION CORRECTIVE  ACTION a. NOISE WHEN DRIVING. Step 1. Check  lubricant  level. If level is low,   inspect for leaks. If leak exists,   take  necessary  corrective  action. If level is low and no leaks exist, refill lubricant to  proper level, refer to LO 10-3930-643-12. Step 2. Inspect for scored or damaged wheel bearings. If wheel bearings are satisfactory, install  and  check  for possibility of improper adjustment of wheel bearing, refer to paragraph 7-5 for wheel bearing inspection, replacement or adjustment. If wheel bearings are operating, proceed to Step 3. Step 3. Check for bent shaft or worn or damaged gear teeth on axle shaft. Replace, refer to paragraph 7-2 or 7-3 for front axle and 7-6 or 7-7 for rear axle. If axles are satisfactory, proceed to Step 4. Step 4. Inspect ring gear and bearings in planetary. If damaged, replace, refer to paragraph 7-5. If damage is to planetary carrier assembly, contact General Support. If planetary is functioning, proceed to Step 5. Step 5. Differential pinion and ring gear adjustment too tight. Contact General Support. 7-2