For 1990-2009 cars

Notice: The transmission fluid level must be checked before fluid leak diagnosis is performed to prevent damage to the transmission.

Check transmission fluid level. Refer to Transmission Fluid Check .

### General Method

1. Verify that the leak is transmission fluid.
2. Thoroughly clean the suspected leak area.
3. Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.
4. Park the vehicle over clean paper or cardboard.
5. Shut OFF the engine.
6. Look for fluid spots on the paper.
7. Make the necessary repairs.

### Powder Method

1. Thoroughly clean the suspected leak area with solvent.
2. Apply an aerosol type powder, such as foot powder, to the suspected leak area.
3. Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.
4. Shut OFF the engine.
5. Inspect the suspected leak area.
6. Trace the leak path through the powder in order to find the source of the leak.
7. Make the necessary repairs.

### Dye and Black Light Method

A fluid dye and black light kit is available from various tool manufacturers.

1. Follow the manufacturer's instructions in order to determine the amount of dye to use.
2. Install the dye. Refer to Transmission Fluid Check .
3. Detect the leak with the black light.
4. Make the necessary repairs.

### Find the Cause of the Leak

Pinpoint the leak and trace the leak back to the source. You must determine the cause of the leak in order to repair the leak properly. For example, if you replace a gasket, but the sealing flange is bent, the new gasket will not repair the leak. You must also repair the bent flange. Before you attempt to repair a leak, check for the following conditions, and make repairs as necessary:

#### Sealant Connections

• | Fluid level/pressure is too high

• | Plugged vent or drain-back holes

• | Improperly tightened fasteners

• | Dirty or damaged threads

• | Warped flanges or sealing surface

• | Scratches, burrs, or other damage to the sealing surface

• | Cracking or porosity of the component

• | Improper sealant used, where applicable

#### Seals

• | Fluid level/pressure is too high

• | Plugged vent or drain-back holes

• | Damaged seal bore

• | Damaged or worn seal

• | Improper installation

• | Cracks in component

• | Manual or output shaft surface is scratched, nicked, or damaged

• | Loose or worn bearing causing excess seal wear

### Possible Points of Fluid Leaks

#### Control Valve Body Cover (29)

• | Incorrectly tightened control valve body cover bolts

• | Improperly installed or damaged control valve body cover sealant

• | Damaged control valve body cover or mounting face

#### Case Leak

• | Lube Drain Plug (819)

• | Damaged manual shift shaft seal assembly (713)

• | Loose or damaged fluid cooler pipe fittings

• | Loose fluid pressure plug (40)

• | Porous casting

#### Leak at the Torque Converter End

• | Converter leak in the weld area

• | Converter seal lip cut. Check the converter hub for damage

• | Converter seal bushing moved forward and damaged

• | Converter seal garter spring missing from the seal

• | Porous casting of the transmission case or the fluid pump

#### Leak at the Vent

• | Overfilled system

• | Water or coolant in the fluid. The fluid will appear milky

• | Transmission case porous

• | Plugged vent

• | Drain-back holes plugged

#### Possible Fluid Leaks

(1) | Fluid Pressure Plugs (40)
(2) | Front Wheel Drive Oil Shaft Seal (80)
(3) | Front Differential Carrier Assembly (809)
(4) | Automatic Transmission Fluid Pump Body Seal Assembly (185, 186)
(5) | Torque Converter Assembly (1)
(6) | Automatic Transmission Case Plug
(7) | Automatic Transmission Output Speed Sensor O-ring Seal (76)
(8) | Automatic Transmission Input Speed Sensor O-ring Seal (74)
(9) | Automatic Transmission Wiring Harness Assembly (78)
(10) | Manual Shift Shaft Seal Assembly (713)
(11) | Automatic Transmission Vent Assembly
(12) | Control Valve Body Cover (29)
(13) | Fluid Level Indicator Tube Seal
(14) | Transmission Fluid Cooler Pipe Fittings
(15) | Automatic Transmission Case, or Torque Converter Housing Assembly - Porosity (10, 17)
(16) | Torque Converter Housing Assembly to Automatic Transmission Case (10, 17)
(17) | 2nd and 4th Band Servo Cover O-ring Seal (57)
(18) | Transmission Fluid Drain Plug