Ford Fiesta Quiz
Manual Transmission, Clutch, Transfer Case and Power Transfer Unit

Manual Transmission - Diagnosis and Testing

In this manual: Manual Transmission, Clutch, Transfer Case and Power Transfer Unit
Service Information — 27Suspension — 48Transmission — 9Brake System — 52Steering — 21Engine — 140Manual Transmission, Clutch, Transfer Case and Power Transfer Unit — 48Exhaust System — 6Fuel System — 21Climate Control System — 58Instrumentation and Warning Systems — 26Battery and Charging System — 20Infotainment Systems — 41Lighting — 29Power Distribution — 11Electronic Function Group — 30Body and Paint — 275Frame and Mounting — 3
4steps
~24min
2/5difficulty
Done 0 of 4

Inspection and Verification

NOTICE: If transmission noise is reported, check the fluid level first. Do not operate the vehicle if the fluid level is low or damage may occur.

  1. Verify the customer concern.
  2. Visually inspect for obvious signs of mechanical damage.

Visual Inspection Chart


  • Fluid leaks.
  • Obviously damaged or worn components.
  • Loose or missing nuts or bolts.
  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
  2. If the cause is not obvious, check the symptom and REFER to the Symptom Chart.

Perform the following checks before repairing or installing a new transmission.

Inspection and diagnosis of manual transmission concerns can be approached in three main areas.

Gear Shifting Concerns

  • Check clutch operation: Place a wooden block approximately 25 mm (1 in) thick under the clutch pedal and fully depress the clutch pedal. If first or second gear can be selected with the engine running and the parking brake applied without any problems, the clutch is good.
  • Clutch operates incorrectly.
  • External shift mechanism.
    REFER TO: External Controls (308-06 External Manual Transmission Controls - 6-Speed Manual Transmission - B6).
  • REFER TO Symptom Chart.

Transmission Noise Concerns

  • Check the engine and transmission mounts for sufficient clearance between the transmission and the body.
  • If noise occurs in different gears at the same engine speed, check whether the noise also occurs in neutral. If it does, the noise is not caused by the transmission.
  • Road test the vehicle.
  • REFER TO Symptom Chart.

Fluid Leakage Concerns

  • Check the transmission fluid level. If necessary, drain excess fluid.
  • Using a suitable ultraviolet fluid leak detection kit, locate the leak and check whether the leaking fluid is transmission fluid, brake fluid (from the hydraulic clutch) or engine oil.
  • Thoroughly clean the transmission and surrounding areas before road testing.
  • REFER TO Symptom Chart.

Symptom Chart - Transmission Operation

Symptom Possible Sources Action
  • Gears clash when shifting from one forward gear to another.
  • Gear teeth/synchronizer damaged.
  • CHECK and REPAIR as necessary.
    REFER TO: Transmission (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Transmission jumps out of gear.
  • Transmission-to-engine bolts loose.
  • Incorrect preload.
  • Internal components damaged.
  • Gear teeth worn/damaged.
  • TIGHTEN bolts to specification.
    REFER TO: Transmission (308-03C).
  • CHECK preload. CHECK synchronizer for free play in their assemblies. CHECK synchronizer blocking rings for worn index slots, rounded engagement teeth and a smooth inner surface. Check the countershaft gear for excessive end play. CHECK shift fork for wear. CHECK whether shift forks are loose on the shift rails. INSPECT sliding synchronizer sleeve and dog teeth for wear and damage. REPAIR as necessary.
    REFER TO: Transmission (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Transmission does not shift into one gear - all others are good.
  • Internal Components
  • For the gear in question, CHECK the shift rail and fork, synchronizer and dog teeth for travel restriction. REPAIR as necessary.
    REFER TO: Transmission (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Transmission locked in one gear and will not shift out of that gear.
  • Internal Components
  • CHECK gears, shift rails, forks and synchronizer for wear or damage. REPAIR as necessary.
    REFER TO: Transmission (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Fluid Leaks
  • Transmission Fluid
  • Other components leak.
  • Axle shaft seals.
  • Input shaft seal.
  • Fill and drain plugs.
  • CHECK transmission fluid level and type.
  • CLEAN all fluid residue from the exterior surfaces of the transmission. CHECK that the vent is not blocked and breathes freely. OPERATE the transmission and CHECK for new leaks. DETERMINE whether the leaking fluid is from the engine, the power steering or the transmission fluid. REPAIR as necessary.
  • CHECK and, if necessary, INSTALL new seals.
    REFER TO: Left Axle Shaft Seal (308-03C).
    REFER TO: Right Axle Shaft Seal (308-03C).
  • CHECK and REPAIR as necessary.
    REFER TO: Input Shaft Seal (308-03C).
  • INSPECT the plug, the sealing washer and the threads in the case. REPAIR as necessary. TIGHTEN the plug to specification.
    REFER TO: Transmission Fluid Level Check (308-03C).
  • Considerable force is required to shift into a lower gear.
  • Insufficient gear synchronization. Gear teeth/synchronizer damaged.
  • CHECK the transmission. INSTALL a new synchronizer assembly with synchronizer rings. INSTALL two new gears belonging to the synchronizer assembly.
    REFER TO: Transmission Case (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Hard shifting
  • Transmission Fluid
  • Synchronizer rings or internal shift mechanism damaged
  • CHECK that the transmission is filled with the specified transmission fluid and, if necessary, FILL and ADD transmission fluid as required.
  • CHECK the internal components for wear or damage. REPAIR as necessary.
    REFER TO: Transmission Case (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Unable to select one of the gears
  • Malfunction between the shift lever and the shift lever housing
  • CHECK the shift lever.
    REFER TO: External Controls (308-06E).
  • Unable to select reverse gear
  • Shift lever
  • Internal Components
  • CHECK the shift lever for damage. REPAIR as necessary. Remove the shift lever to check whether reverse gear can be engaged.
  • CHECK the reverse idler gear, the corresponding shift fork, the shift rail and the synchronizer assembly. REPAIR as necessary.
    REFER TO: Transmission Case (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Grinding or clunking when shifting into 3rd gear
  • Improper lubrication causing premature wear of 3rd gear.
  • INSTALL a new 3rd gear, 3rd/4th shift fork, outer synchronizer ring, inner synchronizer ring, 3rd gear synchronizer cone and 3/4 synchronizer assembly.
    REFER TO: Transmission Case (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).

Transmission NVH Symptom Chart

Symptom Possible Sources Action
  • Noise in forward gears - noise described as rattling or knocking
  • Low transmission fluid level/incorrect fluid type
  • Grounding of transmission components
  • Bearings/gears worn/damaged
  • Transmission-to-engine bolts loose.
  • ADD or FILL the specified transmission fluid.
    REFER TO: Transmission Fluid Level Check (308-03C).
  • CHECK that the screws and bolts of the chassis components are not grounded. REPAIR as necessary.
  • CHECK the bearings, gears and gear teeth for wear and damage. REPAIR as necessary.
    REFER TO: Transmission Case (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • ENSURE that the bolts are tightened to specification.
    REFER TO: Transmission (308-03C).
  • Noise in NEUTRAL occurs after warm-up or under load.
  • Neutral noise when coasting
  • Infection Transmission
  • A slight gear noise when coasting is an acceptable condition. INSTALL a new clutch disc.
    REFER TO: Clutch Disc and Pressure Plate (308-01E).
  • CHECK and REPAIR as necessary.
    REFER TO: Transmission (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Slight humming, rattling or metallic grinding from the transmission at 2500 to 3500 rpm during coasting or no-load driving (especially in 2nd and 3rd gear)
  • Engine vibration not sufficiently damped by the clutch
  • These noises do not affect the operation or durability of the transmission.
  • Brief grinding when shifting gears
  • Insufficient gear synchronization
  • CHECK the transmission for wear or damage. REPAIR as necessary. INSTALL a synchronizer assembly with synchronizer rings. INSTALL two new synchronizer gears.
    REFER TO: Transmission Case (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Gear whine - if it occurs, load the engine in 1st or 2nd gear, depress the accelerator pedal fully, and the noise will be audible.
  • Reduced preload on the input shaft
  • Acceptable noise under these conditions.
  • Gear whistle - occurs in 2nd, 3rd and 4th gear when the throttle is depressed fully and the vehicle accelerates rapidly to WOT; a very faint whistle is audible.
  • Driven gears on the countershaft
  • Acceptable noise under these conditions.
  • Clicking in reverse gear
  • Reverse Gear
  • CHECK the gears for wear or damage. INSTALL new gears as necessary.
    REFER TO: Transmission Case (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Disassembly).
  • Clicking, rattling or rubbing noises in neutral with the clutch pedal released; vehicle not moving
  • Normal noise when engaging gears
  • The noise when shifting gears will disappear when the clutch pedal is fully depressed, the clutch is disengaged, or the transmission is in gear. The rattling noise associated with a manual transmission is caused by constantly meshed gears rotating with the engine at idle, with the clutch engaged and the transmission in NEUTRAL.

Pinpoint Tests


PINPOINT TEST G: EXCESSIVE NOISE
G1 TRANSMISSION NOISE CHECK AT IDLE (A)
  • Start the engine.
  • Fully depress the clutch pedal.

Is the noise heard when the clutch is engaged?
Yes GO to G2
No There is a transmission concern.
Refer to: Manual Transmission (308-03B Manual Transmission - 6-Speed Manual Transmission - B6, Diagnosis and Testing).
.
G2 TRANSMISSION NOISE CHECK AT IDLE (B)
  • Start the engine and allow it to idle.

Is the noise coming from the pedal?
Yes CHECK the clutch pedal and bushings.
No GO to G3
Refer to: Clutch Controls (308-02 Clutch Controls - 6-Speed Manual Transmission - B6). .
G3 CHECK THE CLUTCH RELEASE BEARING
  • Remove the clutch slave cylinder/release bearing assembly.
    REFER TO: Clutch Slave Cylinder - 5-Speed Manual Transmission - B5/IB5 (308-02 Clutch Controls - 5-Speed Manual Transmission - B5/IB5/6-Speed Manual Transmission - B6, Removal and Installation).
  • Inspect the release bearing for wear and corrosion.

Are there any signs of wear or corrosion?
Yes INSTALL a new clutch release bearing.
REFER TO: Clutch Slave Cylinder - 5-Speed Manual Transmission - B5/IB5 (308-02 Clutch Controls - 5-Speed Manual Transmission - B5/IB5/6-Speed Manual Transmission - B6, Removal and Installation).
No CHECK the crankshaft for excessive end play.

Test yourself

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