Transfer Case Will Not Shift
| Cause | Correction | ||
|---|---|---|---|
| DEFINITION: The transfer case will not shift from 2 wheel drive to 4 wheel drive or there is a gear clashing when shifting from Hi to Lo modes. When shifting from 2HI or 4HI to 4LO, the transmission must be in neutral and the vehicle speed below 3 mph. 1. Review the correct owners manual shifting procedures with the customer. 2. Inspect for the correct fluid level. 3. Inspect the drain plug for large metal deposits. Small metal flakes and fine metal dust on the plug magnet are to be considered normal. Review the Symptoms - Transfer Case and perform the necessary inspections. | |||
| Front axle actuator | Note: A transfer case that will not shift into 4WD may be caused by the front axle actuator. If the symptoms occur during cold temperatures, flush and fill the front axle with synthetic fluid. Front Axle Lubricant Level Inspection 1. Perform the Diagnostic System Check - Vehicle before using the symptom tables, in order to verify the following conditions are true: There are no diagnostic trouble codes (DTCs) present. The control modules can communicate via the serial data link. 2. Inspect for an intermittent. Faulty electrical connections or wiring may be the cause of intermittent conditions. Testing for Intermittent Conditions and Poor Connections Some symptoms may be caused by loose wiring. Test the system after moving or connecting harnesses, but before replacing parts. Four-Wheel Drive Does Not Engage | ||
| Electrical system | 1. Perform the Diagnostic System Check - Vehicle before using the symptom tables, in order to verify the following conditions are true: There are no diagnostic trouble codes (DTCs) present. The control modules can communicate via the serial data link. 2. Inspect for an intermittent. Faulty electrical connections or wiring may be the cause of intermittent conditions. Testing for Intermittent Conditions and Poor Connections Some symptoms may be caused by loose wiring. Test the system after moving or connecting harnesses, but before | ||
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| Cause | Correction |
|---|---|
| Transfer case shift fork pads broken or missing | Note: A growl, rattle, or grinding noise that occurs when a shift is commanded may be caused by broken or missing shift fork pads which may lead to incomplete engagement of the high/low clutch teeth. High/Low Shift Components Cleaning and Inspection Replace the shift forks and pads as required. Transfer Case Disassemble and Transfer Case Assemble |
| Transfer case high/low clutch gear tooth damage | Note: Excessive gear tooth damage may cause a will not shift or gear clash when shifting condition. 1. Inspect the gear teeth for excessive damage. High/Low Shift Components Cleaning and Inspection 2. Inspect the splines of the high/low clutch and rear output shaft to ensure the clutch moves freely on the shaft. 3. Replace components as required. |
| Clutch pack | A worn clutch pack may set a DTC and disable shifting. Diagnostic System Check - Vehicle |
| Shift levers and shift components | Note: An incorrect technician repair using mismatched heavy duty (HD) and light duty (LD) shift levers and shift lever balls may lead to a will not shift condition. Refer to Transfer Case Description and Operation for additional shift lever and shift lever ball information. 1. Apply plate installed incorrectly after a service overhaul. 2. Worn shift lever components may set a DTC and disable shifting. Diagnostic System Check - Vehicle |
| Rear output shaft snap ring broken or out of position | Note: A broken or mis-positioned rear output shaft snap ring may lead to a will not shift condition. Inspect for a broken or mis-positioned rear output shaft snap ring. |
| Transfer case high/low planetary carrier assembly | Note: In situations where there is excessive input shaft gear teeth wear, it may not be possible to engage 4LO. 1. Inspect the planetary gears and high/low internal gear for wear or damage. High/Low Planetary Carrier Cleaning and Inspection 2. Inspect the input shaft gear teeth for wear or damage 3. Replace components as required. |