Hummer H1 (2006+). Manual - part 256

9-2 Axles, Suspension and Frame

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Inspection  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-73
Intermediate Body Mount Bracket

Left  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-97
Right . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-96

Lifting Shackle   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-109
Radiator Front Mount Bracket  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-86
Rear Bumper  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-108
Rear Suspension Rear Crossmember   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-107
Repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-77
Splash Shield Support Bracket  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-91
Tiedown Bracket

Rear-Front  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-100
Rear-Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-98

Transmission Crossmember Support   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-95
Transmission Mount Crossmember  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-94
Transmission Mount Replacement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-95

Suspension System   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-39–9-72

Ball Joint Replacement

Lower  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-65
Upper  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-63

Coil Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-70
Control Arm Replacement

Bushing  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-67
Lower  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-68
Upper  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-65

Frame Extension Replacement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-86
Geared Hub  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-40

Input Seal Replacement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-44
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-46
Side Cover Replacement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-44
Spindle Bearing Adjustment  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-57
Spindle Seal Replacement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-54
Spindle Stud Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-60
Vent Line Replacement   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-60

General Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-39

Specifications  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-39

Radius Rod  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-72
Shock Absorber   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-71
Stabilizer Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-61

Link Replacement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-62

Tools

Essential   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-111
Special  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-112

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 Axles, Suspension and Frame  9-3

AXLE ASSEMBLY AND DIFFERENTIAL

General Information

The H1 standard differential is a ZEXEL Torsen

®

II with a 2.56:1 ring and pinion ratio. Both front and rear axle housings contain

this differential. The Torsen II differential provides full time differentiation, full time maximum traction and “Torque and Load
Sensing” capabilities. These features provide improved handling, steering and enhanced off-road mobility. 

The H1 optional ELocker

TM

differential is housed in the same axle assembly and has the same ratio of 2.56:1. The main difference is the

drivers ability to “Lock” the differential electronically before entering an obstacle. 

Specifications

Standard Differential: Torsen II

Optional Differential: ELocker

ELocker

TM

 (Option) Normal Operation

To lock the rear differential the driver must first place the transfer case in “L” low range. With the vehicle speed below 3 mph the
ELocker switch must be pressed “ON”. This will cause the module to command the ELocker activation. 

The front differential coil will only lock when the rear has met suitable conditions and is engaged. Axle engagement is represented
with a solid illumination of the light on the corresponding switch.

If the coil engagement is prohibited due to any of a number of reasons (excessive vehicle speed, “L” low range not selected, mechanical
problems etc.) the switch mounted light will flash. The light will continue to flash for 15 seconds, if the criterion to engage the ELocker is
not met in this time the lock request will be discarded. 

The front differential coil will only remain engaged for a three minute time period. At 2.5 minutes the indicator light on the instrument
panel will begin to flash. If the switch is not activated within 30 seconds of the flashing indicator light, the front differential will unlock. If
the rear differential is unlocked for any reason, the front ELocker will be commanded to unlock.

Either differential coil can be disengaged by pressing the “OFF” side of the operator switch and releasing it  (Figure  9-1) . If the ELocker
module sees that the vehicle has been shift.ed out of “L” low range or if the vehicle has been turned off, the module will automatically re-
lease the front and rear differential coil.   

Lubrication

 75/90 Synthetic Gear Oil

Ratio:

 2.56:1

Torque Bias:

 2.3:1

Lubrication:

 75/90 Synthetic Gear Oil 

Ratio: 2.56:1

 General Diagnostics

PROBLEM

POTENTIAL CAUSE

CORRECTION

CLUNKING

1.

Broken ring or pinion tooth

2.

Worn pinion bearing

3.

Worn carrier bearing

4.

Excessive backlash

1.

Replace ring and pinion

2.

Replace pinion bearing 

3.

Replace carrier bearing

4.

Inspect and adjust backlash

WHINING

1.

Mis adjusted or worn carrier bearing

2.

Mis adjusted or worn pinion bearing

3.

Improper ring to pinion interface

1.

Inspect, adjust and/or replace the carrier bearing

2.

Inspect, adjust and/or replace the pinion bearings 

3.

Set the ring to pinion interface

VIBRATION 
at low speeds 
when turning

Improper lubrication or lack of friction modifier

Replace the lubrication and add friction modifier as
needed (Torsen differentials)

9-4 Axles, Suspension and Frame

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Figure 9-1:   ELocker Switches

Diagnostic Trouble Codes

Figure 9-2:   ELocker Warning Light

Codes

Codes are retrieved using flash technology. When activated, the locker warning light (Figure  9-2) on the coolant/fuel module will
flash a series of pulses. These pulses are used to determine which code is present in the ELocker module memory. 

Two types of codes can be retrieved from the ELocker module. 

Configuration code: Two-digit blink codes that indicate the number of coils and hall effect sensors present in the system and
where these devices are located. These codes can be retrieved by pressing the “ON” side of either operator switch and holding for
10 seconds before releasing. Trucks equipped with a rear ELocker only will have configuration code 3-1, if both front and rear are
present the code will be 4-1. The configuration code will be followed by the software version.

Fault Codes are also two-digit blink codes that indicate a problem that the ELocker module has detected. These codes can be re-
trieved by pressing the “OFF” side of either operator switch and holding for 10 seconds before releasing. Codes are listed below.

Erasing Fault Codes is accomplished by performing the configuration code retrieval procedure.

 ELocker

TM

 Fault Codes

Front

Rear 

General

Time to Log

Description

1-1

2-1

300 mSec

Coil shorted to ground or short to voltage

1-2

2-2

60 Sec.

Coil open or short to ground

1-3

2-3

60 Sec.

Operator switch stuck “ON”

1-4

2-4

60 Sec.

Operator switch stuck “OFF”

3-1

60 Sec.

Transfer case range switch shorted to ground

3-2

60 Sec.

Battery not connected

3-3

60 Sec.

Low battery voltage

4-4

60 Sec.

No trouble found

Rear

Front

SWITCH

MOUNTED

LIGHT

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 Axles, Suspension and Frame  9-5

Figure 9-3:   ELocker Circuit