TM   10-3930-638-24&P 4-2.   ENGINE   MAINTENANCE   (cont) h. Timing Gear Cover (cont). STEP LOCATION ITEM ACTION REMARKS CLEANING  (cont) 6 All parts Clean Use cleaning solvent P-D-680. Dry thor- oughly with moisture free compressed air or clean cloth 7 Idler gear (11) and Inspect Inspect  gear  for  damage,  distortion,  and bushing (12) missing or broken teeth. Check gear teeth for pitting. If any of these condi- tions observed replace gear and bushing as an assembly. Use bore gage and mea- sure inside diameter of idler gear bushing. Measure bore gage using micrometer. If bushing inside diameter is more than 1.377 inches, replace gear and bushing as an assembly Idler gear hub (13) Inspect 8 Inspect for cracks, pitting, and distortion. Replace if any of these conditions ob- served. Use micrometer and measure outside diameter of hub shaft. Diame- ter must be not less than 1.3740 inches; replace part if diameter is less than this dimension Timing gear cover (27) Inspect 9 Inspect for cracks and distortion; replace if cracked or distorted. Check threads on studs (28 and 29) for damage; if threads are damaged or if studs bent replace studs. Replace stud (28) by driving it out of cover using soft hammer, insert new stud in cover, install 3/8-16 nut, and tighten nut to draw stud into mounting hole. Remove  nut.  Replace  stud  (29)  by unscrewing it and installing new stud All  other  parts Inspect 10 Check for cracks, damage, and distortion; replace part if any of these conditions observed INSTALLATION 11 Crankshaft Oil slinger (31) Install On end of crankshaft. Cupped surface toward crankshaft gear. Align notch on oil  slinger  with  keyway  on  crankshaft 4-64 Change   1