DEFINITION: While shifting from HI range to LO range, there is gear clashing or no HI range; or the transfer case will not shift from 2 wheel drive to 4 wheel drive.

Review the Symptoms - Transfer Case and perform the necessary inspections.

Mode shift clash

1. Disassemble the transfer case. Refer to Transfer Case Disassemble in Transfer Case - Isuzu T150 Unit Repair.
2. Inspect the synchronizer components for being faulty. Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.
3. Replace the synchronizer if faulty. Refer to Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

Mode block

1. Disassemble the transfer case. Refer to Transfer Case Disassemble in Transfer Case - Isuzu T150 Unit Repair.
2. Inspect the synchronizer sleeve for sliding freely.
3. Inspect the synchronizer for being faulty.
4. Replace the synchronizer if faulty. Refer to Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

High/low range shift fork assembly

1. Inspect the high/low shift fork assembly for the following conditions:

•	The roller on the shift block for wear or damage

•	Shift shaft spring broken

•	Worn or melted range fork pads

•	Bent shift shaft

•	Cracked or bent shift fork

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.

2. Replace the high/low shift fork assembly if found faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

High/low range sleeve

1. Inspect the high/low range sleeve for the following conditions:

•	Engagement teeth for burrs or damage

•	Sliding freely on the rear output shaft

•	The range sleeve shift fork collar for excessive wear

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.

2. Replace the range sleeve if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

Rear output shaft front support bearing

1. Inspect for the following conditions:

•	Failed needle bearing in the input gear

•	Journal on the rear output shaft for excessive wear or damage

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.

2. Replace the bearing if faulty.
3. Replace the rear output shaft if damaged.

Planetary carrier low gear

1. Inspect the engagement teeth on the planetary carrier low gear for burrs or damage. Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.
2. Replace the planetary carrier low gear if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

2/4 Wheel drive shift fork assembly

1. Inspect the 2/4 wheel drive shift fork assembly for the following conditions:

•	The roller on the shift block for wear or damage

•	Shift shaft spring broken

•	Bent shift shaft

•	Worn shift fork pads

•	Cracked or bent shift fork

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.

2. Replace the 2/4 wheel drive shift fork assembly if found faulty.

Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

Control actuator cam

1. Inspect for the following conditions:

•	The control actuator cam at the shift fork cams for being worn

•	The bushing for the control actuator cam shaft for being worn

2. Replace the following components if found faulty:

•	The control actuator cam

•	The bushing for the control actuator shaft

•	Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

Drive sprocket

1. Inspect for the following conditions:

•	Synchronizer engagement teeth on the drive sprocket for burrs or damage

•	Worn bushing in the drive sprocket

•	Journal on the rear output shaft for excessive wear or damage

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.

2. Replace the drive sprocket if it is damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.
3. Replace the rear output shaft if it is damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.