Section 07-03: Transmission, Manual—T50D
1993 Mustang Workshop Manual
DIAGNOSIS

Transmission, Manual—T50D

Refer to the following diagnosis charts when servicing the T50D transmission.

NOTE: Gear rollover noise, inherent in manual transmissions, (caused by the constant mesh gears turning at engine idle speed while the clutch is engaged and the transmission is in NEUTRAL), and clutch release bearing noise are sometimes mistaken for mainshaft bearing noise. Noise caused by a worn or damaged clutch release bearing will be loudest when the clutch is held disengaged. Gear rollover noise will disappear when the clutch is disengaged or when the transmission is engaged in gear. In the event that a transmission bearing is damaged, the noise is more pronounced while engaged in gear under load or coast conditions than in NEUTRAL. When concerns of this nature are encountered, it will be necessary to road test the vehicle to determine if bearing noise exists. Under no circumstances should any transmission rework be attempted to eliminate gear rollover noise, or clutch release bearing noise.

TRANSMISSION DIAGNOSIS
ConditionPossible SourceAction
  • Transmission Noisy in Gear
  • Lubricant level low or wrong type.
  • Fill to bottom of filler plug hold with proper lubricant.
 
  • Transmission to flywheel housing and flywheel housing to engine block bolts loose.
  • Tighten bolts to 61-88 Nm (45-65 lb-ft).
 
  • Pilot bushing worn or damaged.
  • Remove transmission. If noise is howling during start-up, check pilot bushing. Check for loose flywheel and housing alignment. Service or replace as required. Refer to Section 08-00.
 
  • Improper transmission pilot engagement into flywheel housing.
  • Replace housing or input shaft bearing retainer as required. Refer to Section 08-00.
 
  • Worn or damaged internal components.
  • Disassemble transmission. Inspect input, output and countershaft bearings, gear and gear teeth for wear and damage. Service or replace as required.
  • Transmission Leaks
  • Excessive amount of lubricant in transmission—wrong type.
  • Check level and type. Fill bottom of filler plug hole.
 
  • Other component(s) leaking.
  • Identify leaking fluid at engine, power steering and/or transmission.
 
  • False report.
  • Remove all traces of lubricant on exposed transmission surfaces. Check vent for free breathing. Operate transmission and inspect for new leakage. Service as required.
 
  • Worn or damaged internal components.
  • Remove transmission. Inspect for leaks at the input shaft bearing retainer seal and gasket, shift rail expansion plug top cover gasket. Inspect case for sand holes. Service or replace as required.
 
  • Inadequate thread sealant on threads.
  • Apply sealant to bolt threads.
  • Transmission Shifts Hard
  • Improper clutch release.
 
  • Internal shift mechanism binding.
  • Remove transmission and free up shift mechanism.
 
  • Synchronizer sleeve to hub fit.
  • Remove and check for burrs or fit.
 
  • Binding condition between input shaft and crankshaft pilot bearing.
  • Check alignment and service as required. Refer to Section 08-00.
 
  • Improper fluid.
  • Drain and refill with Synthetic MERCON® Multi-Purpose Automatic Transmission Fluid E6AZ-19582-B (ESR-M2C163-A2) or equivalent to bottom of filler plug hole.
  • Gears Clash When Shifting from One Forward Gear to Another
  • Engine idle speed too high.
  • Adjust engine idle speed.
 
  • Improper clutch release.
 
  • Binding condition between transmission input shaft and crankshaft pilot bushing.
 
  • Worn or damaged shifter forks, synchronizer assembly, or gear clutch teeth.
  • Service or replace as required.
  • Transmission Jumps Out of Gear
  • Floor shift—stiff or improperly installed boot.
  • Verify jump-out with boot removed. Replace boot if necessary.
 
  • Floor shift—interference between shift handle and console.
  • Adjust console to eliminate interference.
 
  • Transmission to engine mounting loose.
  • Tighten bolts to specification.
 
  • Flywheel housing to engine crankshaft out of alignment.
 
  • Improper engagement between transmission pilot and flywheel housing.
 
  • Input shaft pilot bearing worn.
 
  • Worn or damaged internal components.
  • Check input and output shafts for excessive end play, shift forks for loose mounting on shift rails, worn pads, shift rail detent system for wear or damage, synchronizer sliding sleeve and gear clutch teeth for wear or damage. Service or replace as required.
  • Transmission Will Not Shift Into One Gear—All Other Gears OK
  • Floor shift, interference between shift handle and console or floor cut out.
  • Adjust console or cut out floorpan to eliminate interference.
 
  • Restricted travel of internal shifter components.
  • Remove transmission. Inspect shift rail and fork system, synchronizer system and gear clutch teeth for restricted travel. Service and replace as required.
  • Transmission is Locked in One Gear. It Cannot be Shifted Out of that Gear
  • Internal shifter components worn or damaged.
  • Remove transmission. Inspect the problem gear or gearshift rails and fork and synchronizer for wear or damage. Service or replace as required.
 
  • Selector arm finger broken.
  • Remove transmission. Replace selector arm assembly.
 
  • Bent shifter forks at pads and selector slot.
  • Service or replace as required.
  • Transmission Will Not Shift Into Reverse (All Others OK)
  • Worn or damaged internal components.
  • Remove transmission. Check for damaged reverse geartrain, misaligned reverse relay lever, shift rail and fork system. Service or replace as required.