TM 10-3930-659-34 4-8. IDLER GEARS MAINTENANCE (Con’t). NOTE If replacing upper or lower idler gearshaft, springpin must also be replaced. 7. Using vernier caliper, measure outside diameter of upper or lower idler gearshaft. Outside diameter must measure 1.749-1.750 in. (4.442-4.445 cm). Replace worn upper or lower idler gearshaft. 8. Inspect  sleeve  bushings  for  grooves.  Using  vernier  caliper,  measure  inside  diameter  of  sleeve  bushing.  Inside diameter must measure 1.751-1.753 in. (4.448-4.453 cm). Replace damaged or worn upper or lower idler gear. 9. If  end  play  recorded  in  subparagraph  a,  steps  2  and  11,  was  not  within  specification  and  idler  gears  are  within specification, replace thrustwashers. d. ASSEMBLY 1. If  removed,  install  springpin  (18)  on  upper  idler gearshaft   (14)   until   springpin   extends   beyond surface  of  upper  idler  gearshaft  0.138-0.177  in. (3.505-4.496 mm). 2. If  removed,  install  springpin  (20)  on  lower  idler gearshaft    (4)    until    springpin    extends    beyond surface  of  lower  idler  gearshaft  0.197-0.275  in. (5.004-6.985 mm). e. INSTALLATION NOTE Perform steps 1 and 2 only if upper idler gearshaft was removed. 1. Install thrustwasher (13) on upper idler gearshaft (14) and springpin (18). 2. Apply lubricating oil to upper idler gearshaft (14) and position upper idler gearshaft on cylinder block front plate (1). 3. Using gear timing tool, aline timing marks on fuel injection pump gear (12), camshaft gear (19), and crankshaft (2). TA708083 4-40