Hummer H3. Manual — part 1463

on the speed gear selector teeth

Were you able to shift into the gear
position that has the concern?

Go to Step 7

Go to Step 6

6

1. Remove the transmission. Refer to

Transmission Replacement.

2. Disassemble the transmission. Refer

to Transmission Disassemble.

3. Inspect the following transmission

internal components for wear or
damage:

The shift forks

The internal shift control lever

Did you find and repair the condition?

Go to Step 8

Go to Step 7

7

1. Remove the transmission. Refer to

Transmission Replacement.

2. Disassemble the transmission. Refer

to Transmission Disassemble.

3. Inspect the following transmission

internal components for wear or
damage:

The synchronizer sleeve selector
teeth

The speed gear selector teeth

The speed gear axial clearance
for being excessive

The speed gear to mainshaft
bearings and journals

The countershaft for being
broken

The mainshaft for being broken

The countershaft gear for being
stripped

The mainshaft gear for being
stripped

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

TRANSMISSION JUMPS OUT OF GEAR

Diagnostic Aids

If the transmission jumps out of gear during deceleration, inspect the components that may allow
for the gears or shafts to tip. If the gears or shafts tip, the synchronizer sleeve can disengage from
the selector teeth on the speed gear. If the transmission jumps out of gear during acceleration,
inspect the components that may not allow full engagement of the synchronizer sleeve to the
selector teeth on the speed gear. Insufficient engagement of the selector teeth under torque may
cause the transmission to jump out of gear.

Test Description

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

2: A static shift test is performed by shifting into all gear positions with the engine not
operating. While performing the test, slowly move the shift lever. Feel for proper movement
of the shift lever and transmission internal shift components.

4: A dynamic shift test is performed by shifting into all gear positions with the engine
operating. Test for the correct mesh of the synchronizers sleeve and the speed gear selector
teeth. Move the shift lever and feel for the synchronizer sleeve to release form the gear and
then let up on the clutch pedal. Depress the clutch pedal and move the shift lever to engage
the gear again, to ensure full travel of the shift components.

5: This step inspects for worn or damaged transmission or engine mounts. Loose mounts may
cause a shock on the transmission, allowing for gear disengagement.

6: This step inspects for the misalignment of the clutch to transmission. Misalignment may
put a bind on the input shaft, allowing for the input shaft or the mainshaft to tip.

8: This step inspects the pilot bearing and the pilot bearing journal on the input shaft. A
worn pilot bearing or input shaft may allow the input shaft to tip, causing gear
disengagement.

Transmission Jumps Out of Gear

Did you find and repair the condition?

Go to Step 8

Go to Diagnostic
Aids

8

Operate the system in order to verify the
repair.
Did you correct the condition?

System OK

Go to Step 1

Step

Action

Yes

No

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

DEFINITION: Gear disengagement occurs during acceleration or deceleration.

1

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

Go to Step 2

Go to Symptoms
- Manual
Transmission

2

1. Perform a static shift test.

2. Test for the following conditions:

Blockage, preventing full shift
lever movement

Excessive movement in the shift
lever

Detent plungers engaging in the
shift rails

Synchronizer pressure pieces on
the synchronizer sleeves

Did the transmission shift completely into
all gears?

Go to Step 4

Go to Step 3

3

Remove the shift control housing and
inspect for worn or faulty components.
Refer to Control Lever and/or Boot
Replacement.
Did you find and repair the condition?

Go to Step 10

Go to Step 4

4

1. Perform a dynamic shift test on the

transmission.

2. Test for the following:

Synchronizer sleeve
engagement to the speed gear
selector teeth

Detent plungers engaging in the
shift rails

Did the transmission shift completely into
all gears?

Go to Step 5

Go to Step 8

5

Inspect the engine and/or transmission
mounts. Refer to Transmission Mount
Replacement.
Did you find and repair the condition?

Go to Step 10

Go to Step 6

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

6

Inspect the clutch housing for loose bolts
or misalignment.
Are there any loose bolts or misalignment?

Go to Step 7

Go to Step 8

7

1. Align the housing, if required.

2. Tighten any loose housing bolts.

Refer to Transmission
Replacement.

Did you find and repair the condition?

Go to Step 10

Go to Step 8

8

1. Remove the transmission. Refer to

Transmission Replacement.

2. Remove the clutch assembly. Refer to

Clutch Assembly Replacement .

3. Inspect the pilot bearing for being

faulty.

4. Inspect the input shaft for excessive

wear at the pilot bearing.

Did you find and repair the condition?

Go to Step 10

Go to Step 9

9

1. Disassemble the transmission. Refer

to Transmission Disassemble.

2. Inspect the following components for

wear or damage:

The shift rails

The detent plungers and springs

The shift forks

The synchronizer sleeve to shift
fork clearance

The synchronizer sleeve and
speed gear selector teeth

The mainshaft to input shaft
bearing and journals

The speed gear bearings and
journals

The speed gear axial clearance

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3