| Subject: | Guidelines for Proper Use of Labor Operation Numbers When Servicing Transfer Case | 
| Models: | 2006 and Prior Passenger Cars and Light/Medium Duty Trucks | 
 | with Four-Wheel Drive (4WD) or All-Wheel Drive (AWD) System | 
 
When servicing the transfer case, some dealers are using the incorrect labor operation number when submitting warranty claims. The following information is a guideline to further assist dealers in the proper use of transfer case related labor operation
numbers. This information provides the correct labor operation number/description, vehicle application and vehicle exceptions.
Labor Operation 
 | Description 
 | 
K4120 
 | Switch, Vacuum Control - Replace 
 | 
|     •  | This labor operation applies to NVG 233 and NVG 236 (RPO NP1 and NP8) transfer cases. | 
 
|     •  | The following transfer cases DO NOT incorporate a vacuum switch. Labor operation K4120 will NOT apply to these transfer cases. | 
 
|        -  | NVG 226/236/246 (RPO NP8) | 
 
|        -  | BW 4482/4484/4493 (RPO NR4) | 
 
Labor Operation 
 | Description 
 | 
K4121 
 | Module, Transfer Case - Reprogram 
 | 
The following transfer cases DO NOT incorporate reprogrammable modules. Labor operation K4121 will NOT apply to these transfer cases.
|     •  | Isuzu T150/NVG 233 (RPO NP1) | 
 
|     •  | NVG 246 (RPO NP8) (1998-2002) | 
 
Labor Operation 
 | Description 
 | 
K4122 
 | Module, Transfer Case Shift - Replace 
 | 
The following transfer cases DO NOT incorporate shift control modules. Labor operation K4122 will NOT apply to these transfer cases.
Labor Operation 
 | Description 
 | 
K4123 
 | Switch, Transfer Case Select - Replace 
 | 
The following transfer cases DO NOT incorporate shift select switches. Labor operation K4123 will NOT apply to these transfer cases.
Labor Operation 
 | Description 
 | 
K4124 
 | Sensor Assembly, Transfer Case Range Selector - Replace 
 | 
The following transfer cases DO NOT have replaceable actuator position sensors. Labor operation K4124 will NOT apply to these transfer cases.
|     •  | NVG 246 (RPO NP8) (1998-2002) | 
 
|     •  | BW 4482/4484/4493 (RPO NR4) | 
 
Labor Operation 
 | Description 
 | 
K4126 
 | Actuator Assembly, Transfer Case - Replace 
 | 
The following transfer cases are NOT equipped with actuator assemblies. Labor operation K4126 will NOT apply to these transfer cases.
RPO Definitions
RPO 
 | Description 
 | 
NP1 
 | Transfer Case - Electronic Shift Control, Two-Speed 
 | 
NP2 
 | Transfer Case - Manual Shift Control, Two-Speed 
 | 
NP3 
 | Transfer Case - All Wheel Drive (AWD) 
 | 
NP4 
 | Transfer Case - Active, All Wheel Drive (AWD) 
 | 
NP8 
 | Transfer Case - Active, Two-Speed, Push Button Control 
 | 
NR3 
 | Transfer Case - All Wheel Drive (AWD), Open Diff., Single Speed 
 | 
NR4 
 | Transfer Case - Four Wheel Drive (4WD), Open Diff., Two-Speed 
 | 
NR6 
 | Transfer Case - Four Wheel Drive (4WD), Open Diff., Two-Speed, High Ratio 
 |