Hummer H3. Manual — part 1465

use of the correct type of transmission fluid. The incorrect type of sealer may not be compatible
with the transmission fluid or may not have the correct characteristics for sealing the affected
components. Ensure the use of the correct type of sealers. Refer to Sealers, Adhesives and
Lubricants.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

3: Use an approved method to clean the transmission, to ensure the leak location is correctly
identified. If using a powder method or dye method, ensure the products are compatible
with the transmission fluid.

6: With the 4WD application, the sealing surface, for the transmission rear seal, is on the
transfer case input shaft.

7: With the 4WD application, a weep hole is located at the transfer case to transmission
flange. If fluid is leaking at the weep hole, verify if it is transmission fluid or transfer case
fluid.

18: Two bolts, for the clutch housing, require the use of sealer.

Transmission Fluid Leak Diagnosis

Step

Action

Yes

No

DEFINITION: Visible sign of the transmission fluid leaking from the transmission.

1

Did you review the Symptoms - Manual
Transmission and perform the necessary
inspections?

Go to Step 2

Go to Symptoms

- Manual

Transmission

2

1. Inspect for the transmission fluid level

being higher than the recommended
level. Refer to Transmission Fluid
Replacement.

2. Adjust the transmission level if

incorrect.

Was the transmission fluid level too high?

Go to Step 31

Go to Step 3

Verify the location of the leak.

1. Clean the transmission assembly.

2. Operate the vehicle for 24 km (15 mi)

or until normal operating

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

3

temperatures are reached.

3. Visually inspect or use the powder

method or dye and black light
method, to locate the leak.

Is the leak occurring at the drain or fill
plug?

Go to Step 4

Go to Step 5

4

Replace the drain or fill plug gasket. Refer
to Transmission Fluid Replacement.
Did you find and repair the condition?

Go to Step 31

Go to Diagnostic

Aids

5

Is the leak at the transmission output shaft
seal?

Go to Step 6

Go to Step 7

6

Remove the output shaft seal and inspect
for the following conditions. Refer to
Transmission Housing Oil Seal
Replacement - Rear.

Damaged or worn seal

Damaged seal bore

Improper installation

Cracks in the component

Propeller shaft yoke sealing surface is
scratched, nicked, damaged or worn

If 4WD, transfer case input shaft seal
surface damaged

Loose or worn bearing causing
excessive seal wear

Did you find and repair the condition?

Go to Step 31

Go to Diagnostic

Aids

7

If 4WD, is the leak at the transfer case to
transmission weep hole?

Go to Step 8

Go to Step 9

1. Remove the transfer case. Refer to

Transfer Case Assembly
Replacement .

2. Inspect the shift shaft plug for

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

8

leaking.

3. Replace the shift shaft plug if leaking.

Refer to Transmission Disassemble
and Transmission Assemble.

Did you find and repair the condition?

Go to Step 31

Go to Diagnostic

Aids

9

Is the leak at the shift lever area?

Go to Step 10

Go to Step 11

10

1. Inspect the shift control lever lower

boot for damage.

2. Inspect for loose shift control housing

mounting bolts.

3. Remove the shift control housing.

Refer to Control Lever and/or Boot
Replacement.

4. Replace the shift control lever lower

boot if damaged.

5. Inspect the shift control lever sealing

surfaces for scratched, nicked or
damaged.

Did you find and repair the condition?

Go to Step 31

Go to Diagnostic

Aids

11

Is the leak at the front of the transmission?

Go to Step 12

Go to Step 21

12

1. Remove the transmission. Refer to

Transmission Replacement.

2. Remove the clutch actuator cylinder.

Refer to Clutch Actuator Cylinder
Replacement .

Is the input shaft seal leaking?

Go to Step 13

Go to Step 14

1. Inspect for the following conditions if

the input shaft seal is leaking:

Damaged or worn seal

Damaged seal bore

Improper installation

Cracks in the component

Input shaft sealing surface is

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

13

scratched, nicked, damaged or
worn

Loose or worn bearing causing
excessive seal wear

2. Replace the input shaft seal if leaking.

Refer to Transmission Input Shaft
Seal Replacement.

Did you find and repair the condition?

Go to Step 31

Go to Step 14

14

Inspect the shift rail plug for leaking.
Is the transmission leaking at the shift rail
plug?

Go to Step 15

Go to Step 16

15

Replace the shift rail plug. Refer to
Transmission Disassemble and
Transmission Assemble.
Did you find and repair the condition?

Go to Step 31

Go to Step 1

16

Inspect for leaking at the front retainer
bolts.
Is the transmission leaking at the front
retainer bolts?

Go to Step 17

Go to Step 18

17

Remove the leaking front retainer bolts and
install with the proper sealer. Refer to
Transmission Disassemble and

Transmission Assemble

.

Did you find and repair the condition?

Go to Step 31

Go to Step 1

18

Inspect for leaking at the clutch housing
bolts.
Is the transmission leaking at the clutch
housing bolts?

Go to Step 19

Go to Step 20

19

Remove the leaking clutch housing bolts
and install with the proper sealer. Refer to
Transmission Disassemble and

Transmission Assemble

.

Did you find and repair the condition?

Go to Step 31

Go to Step 20

20

1. Inspect the case for cracks or

porosity.

2. Replace the transmission front case

half if it is faulty. Refer to

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3