Content .. 52 53 54 55 ..

Hummer H1 (2002+). Manual - part 54

____________________________________________

Transmission/Transfer Case 5-15

05745159

Line Pressure Test

Check and adjust fluid level if necessary.

Raise vehicle on hoist

Connect pressure gauge to transmission test port
(Figure 5-16). Gauge must have 325-350 psi (2240-2413
kPa) capacity.

Start engine and check pressures in Park, Neutral and both
Drive ranges. Pressure should be a minimum of 35 psi
(241 kPa) at idle and increase to a maximum of 171 psi
(1179 kPa) at greater throttle openings.

Shift transmission into reverse and note pressure. At idle,
pressure should be a minimum of 67 psi (462 kPa) and
increase to a maximum of 324 psi (2234 kPa) as throttle
opening increases.

Stop engine, remove gauge, and lower vehicle.

If pressures were low in all ranges, pump may need repair
or replacement. Problem may be worn, damaged gears,
blown out cup plug, cross leakage, or worn bushing. If
pressure is high, fault may be with pressure control
solenoid, reverse/boost or pressure regulator valves, bad
PCM ground or solenoid connection.

Figure 5-16: Pressure Gauge

Pressure Control Solenoid Test

Connect scan tool to diagnostic/data link connector.

Connect pressure test gauge to transmission.

Check fluid level and top off if necessary.

Shift into Park and apply parking brakes.

Start and operate engine at idle speed.

Access “override pressure control solenoid” test on scan
tool.

Increase current to pressure control solenoid in amp
increments shown in chart (Figure 5-17), and record
pressure gauge readings. Allow gauge readings to stabilize
for 3-5 seconds after each current change.

Stop engine and remove test tools.

Compare test pressure readings with charge readings.
Pressures should decrease as current to solenoid is
increased. Consistently high pressures indicate a fault in
the PCM, related wiring, or solenoid. Low pressures
indicate an oil pump fault, or hydraulic circuit fault.

Figure 5-17: Pressure Control Solenoid Test

Specifications

RECOMMENDED FLUID

The recommended and preferred fluid for 4L80-E transmis-
sions is Dexron III.

In cases where Dexron III is not readily available, Dexron IIE
can be used to top off the fluid level. It is not, however, recom-
mended for use as the primary fluid for a fluid change.

Fluid Capacity

Fluid capacity of the 4L80-E used in Hummer vehicles is:

• Transmission refill capacity (after filter change) is ap-

proximately 7.7 qts. (7.3 L).

• Dry fill capacity (after overhaul) is approximately 13.5

qts (12.8 L)

• Cooler and line capacity is approximately 1-2 pts (.47-

.95 L)

NOTE:

Always fill transmission using the dipstick level as a

guide. Residual fluid left in the transmission during service
could result in an overfilled condition.

TRANSMISSION

TEST PORT

PRESSURE GAUGE

Amp Feed To Pressure

Control Solenoid (From

PCM)

Line Pressure - PSI (kPa)

0.0-0.02

157-177 (1083-1220)

0.10

151-176 (1041-1214)

0.20

140-172 (965-1186)

0.30

137-162 (945-1117)

0.40

121-147 (834-1014)

0.50

102-131 (703-903)

0.60

88-113 (607-779)

0.70

63-93 (434-641)

0.80

43-73 (296-503)

0.90

37-61 (255-421)

0.98-1.1

35-55 (241-379)

5-16

Transmission/Transfer Case

_____________________________________________

Fluid Level and Condition

Transmission fluid level and condition are important to proper
operation. An incorrect fluid level can lead to shift problems,
fluid breakdown, and accelerated wear.

Check fluid level and condition during the preliminary inspec-
tion procedure. This is important, as a low fluid level, or over-
fill condition can lead to slip and flare, overheating, burned
fluid, slow engagement, converter shudder, and no fourth gear
upshift.

An overfill condition allows the gear train to churn the fluid
into foam. this action aerates the fluid causing slip, overheat-
ing, oxidation, and overflow from the vent. A low level allows
the pump to take in air along with the fluid. Air in the fluid will
cause pressures to be low and develop slower than normal
shifts.

Checking Fluid Level

Fluid must be at normal operating temperature. Drive
vehicle 10-15 miles (15-24 km) if necessary.

Position vehicle on level surface.

Operate engine at idle speed.

Shift transmission into Park.

Clean dipstick and top of fill tube with shop towel to avoid
dirt entry.

Unlock and remove dipstick (Figure 5-19). Correct fluid
level is to hot full mark at top of crosshatch (Figure 5-18).
Adequate fluid level is anywhere in crosshatch area.

Note color and condition of fluid. Refer to fluid condition
check.

Add fluid only if level is below bottom mark of crosshatch
area. Add fluid in 1/4 to 1/2 pint/liter amounts to avoid
overfill. However, if overfill condition exists, drain
necessary amount of fluid with suction gun and length of
small plastic tubing. Or drain excess off at cooler line with
engine idling.

Install and lock dipstick and shut engine off.

Figure 5-18: Transmission Fluid Level Marks

Figure 5-19: Releasing Transmission Dipstick Lock

Handle

CROSSHATCH

AREA

HOT

FULL MARK

ADD FLUID WHEN

LEVEL IS BELOW

THIS MARK

FILL TUBE

TRANSMISSION

DIPSTICK AND

LOCK HANDLE

LIFT HANDLE

TO UNLOCK

FRONT

VEHICLE

____________________________________________

Transmission/Transfer Case 5-17

05745159

Transmission Fluid Checking Procedure

Step

Action

Value(s)

Yes

Check the fluid color.
Is the fluid color red?

Go to step 2

Go to step 11

Is the fluid level satisfactory?

Go to step 21

Go to step 3

Check the fluid.
Is the fluid foamy?

Go to step 8

Go to step 4

Check the fluid level. The proper fluid level
should be in the middle fo the X-hatch.
Is the level high?

Go to step 9

Go to step 5

Fluid will be low.
Add fluid to the proper fluid level.
Is the fluid level satisfactory?

Go to step 6

Check for external leaks.
Did you find any leaks?

Go to step 7

Go to step 21

Correct the leak condition.
Did you correct the leak condition?

Go to step 21

Is the fluid level too high?

Go to step 9

Go to step 10

Remove excess fluid to the proper level. Refer to
Fluid Changing Proceedure.
Is the fluid level satisfactory?

Go to step 21

Check for contaminants in the fluid.
Drain the fluid to determine the source of the con-
tamination.
Did you drain the fluid?

Go to step 15

Is the fluid color an opaque pink?

Go to step 12

Go to step13

Repair the transmission vent line.
Is teh repair complete

Go to step 15

The fluid color should be light brown. Transmis-
sion fluid may turn dark with normal use. This
does not always indicate oxidation or contamina-
tion.
Is the fluid color light brown?

Go to step 14

Drain the fluid to determine if the fluid is contam-
inated.
A very small amount of material in the bottom
pan is a normal condition, but large pieces of
metal or other material in the bottom pan require
a transmission replacement.
Was the fluid contaminated?

Go to step 15

Go to step 18

Replace the transmission. Refer to transmission
replacement proceedures.
Is the replacement complete?

Go to step 16

5-18

Transmission/Transfer Case

_____________________________________________

SCAN TOOL DIAGNOSIS

NOTE:

The Tech 1 Scan Tool (Figure 5-20) checks function of

the solenoids, sensors, and PCM. The scan tool connector is
attached to the vehicle data link connector (Figure 5-21).The
vehicle requires use of a VIM (Vehicle Interface Mod ule), part
number 7000041.
The scan tool provides data on individual circuits, or on all the
related electrical components in snap shot mode.

The PCM memory and circuits are interrogated by the scan tool.
The tool reads diagnostic trouble codes (DTC) and displays fault
and performance parameters.

Figure 5-20: Tech 1 Scan Tool

Figure 5-21: Data Link Connector

Transmission Warning Lamps

All Hummer vehicles are equipped with a malfunction indica-
tor light (check engine) and a check throttle light. The purpose
of the lights is to alert the driver when a transmission/engine,
or electronic accelerator pedal circuit fault has occurred.

The warning lights are in circuit with the PCM, which controls
light operation. The lights are illuminated for a few seconds at
startup as part of a bulb check and circuit self test routine. The
only other time illumination occurs, is when a system compo-
nent or circuit fault occurs.

Clear TRANS ADAPT.
Is the proceedure complete?

Go to step 17

Add new fluid.
Is the proceedure complete?

Go to step 20

Change the fluid and the filter.
Is the procedure complete?

Go to step 10

Clear TRANS ADAPT.
Is the procedure complete?

Go to step 20

Is the fluid level satisfactory? If not, correct as
needed.

Go to step 21

Perform the Functional Test Procedure.
Is the functional test completed?

System is OK

Transmission Fluid Checking Procedure

Step

Action

Value(s)

Yes

S05-008

DATA LINK

CONNECTOR

I.P.

I.P. CLOSEOUT PANEL

(SHOWN DETACHED)

COURTESY LIGHT

HARNESS

Content .. 52 53 54 55 ..