TM 10-3930-671-24 3. Very   low   stall   rpm   (750   -   1500   rpm)   is   an indication that: a) Torque  converter  stator  is  slipping.    Repair of torque converter is required. b) Engine  has  an  obstruction  in  air  intake  or exhaust system. 4. High   stall   rpm   (greater   than   2400   rpm)   is   an indication of: a) Low transmission clutch pressures, due to: (1)   Inching pedal linkage requires adjustment. (2)   Stuck inching valve. (3)   Weak    (worn)    transmission    charging pump. (4)   Faulty transmission pressure regulator valve. b) Transmission clutch pack disc slippage due to  low  pressure  (see  above),  or  glazing  on the disc surfaces. c) Torque converter blade (fin) damage (loose, bent, or broken). d) Converter spline worn. Transmission Pressure Checks Perform  a  complete  check  of   transmission   pressures, including   individual   clutch   apply   pressures.      Refer   to section 7.3, Transmission Pressure Checks. 1. If    transmission    pressures    are    correct,    check further for: a) Clutch disc glazing, b) Torque converter blade damage, or c) Converter spline wear. 2. To  do  this,  stall  the  engine  at  full  throttle  for  30 seconds, let the engine speed return to idle, then accelerate  the  engine  speed  slowly  again  to  full throttle. a) If   stall   rpm   returns   to   normal,   this   is   an indication that the clutch discs are glazed. b) If stall rpm is greater than normal, this is an indication that the torque converter fins are damaged,   splines   are   worn,   or   clutch   is worn  or  damaged.    Transmission  repair  is required. Test Completion 1. When engine RPM and stall tests are completed, turn the engine off. 2. Remove the tachometer. 3. Lower and latch the seat deck.  Be sure that the seat  deck  is  correctly  latched.    Install  and  close the side doors. 4. Raise  the  truck  and  remove  blocking,  if  used. Lower the drive wheels to the floor. F-91 (F-92 blank)