Knocking? Rattling? Leaking? Review these simple symptoms of common transmission problems to help diagnose your transmission before you bring it in. 

How does an automatic transmission work?

How does an manual transmission work?

Symptom: Clutch Always Applies Or Stalls Vehicle

Possible Problem:

1. Main control assembly gaskets damaged or bolt out of torque.

2. Main control separator plate damaged.

3. Torque Converter Clutch (TCC) solenoid stuck or damaged.

4. Torque converter internal malfunction preventing lockup, piston application.

Symptom: Delay Or Soft Reverse (or) No Forward/Reverse Gear

Possible Problem:

1. Improper fluid level.

2. Filter damaged or plugged.

3. Transmission shift cable and bracket damaged or misadjusted. 

4. Overdrive or Rear one-way clutch damaged.

5. Forward clutch piston check ball not seating.

6. Forward hub seal rings damaged.

7. Forward clutch piston seals cut/worn.

Symptom: External Fluid Leak

Possible Problem:

1. Damaged case vent.

2. Leakage at gasket or seals.

Symptom: Engine Will Not Crank

Possible Problem:

1. Electrical component failure, connection, or wiring harness damage to:

     a. Transmission Range (TR) sensor.

     b. Powertrain Control Module (PCM).

2. Transmission shift cable or bracket damaged or misadjusted.

3. TR sensor misadjusted.

4. Front pump seized.

5. Flywheel damaged.

Symptom: Shift Timing Late Or Early

Possible Problem:

1. No power to Powertrain Control Module (PCM). 

2. Improper band/clutch application pressure.

3. Main control assembly gaskets damaged or bolt out of torque.

4. Main control separator plate damaged.

5. Main control solenoid stuck or damaged.

Symptom: Noise Or Vibration In Forward or Reverse Gear

Possible Problem:

1. Improper fluid level.

2. Pump internal leakage, cavitation.

3. Pump bolts out of torque.

4. Overdrive one-way clutch damaged, worn, or improperly assembled.

5. Rear one-way clutch assembly damaged, worn, or improperly assembled.

AUTOMATIC TRANSMISSION SYMPTOMS

MANUAL TRANSMISSION SYMPTOMS

Symptom: Excessive Cluth Noise

Possible Problem:

1. Worn throwout bearing 

2. Lack of bearing lubrication

3. Bad clutch shaft pilot bearing

4. Insufficient pedal free-play

Symptom: Clutch Slippage ( Little or no movement when clutch is engaged)

Possible Problem:

1. A worn pressure plate or clutch plate

2. Oil soaked clutch plate

3. Insufficient pedal free-play

4. Bad waste or slave cylinder

5. Low fluid

Symptom: Clutch Drags Or Fails To Release

Possible Problem:

1. Too light transmission lubricant or low lubricant level

2. Improperly adjusted clutch linkage

3. Bad cylinder

4. Low fluid

5. Air in line

Symptom: Noise Or Vibration When In Gear

Possible Problem:

1. Low fluid

2. Worn gears (excessive end-play)

3. Worn bearings

4. Damaged synchronizers

5. Chipped gear teeth

Symptom: Noise Or Vibration When In Neutral

Possible Problem:

1. Insufficient/ incorrect lubricant

2. Worn reverse idler gear

3. Worn bearings or gear teeth

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