Transfer case fault diagnostics (Chevrolet Captiva 1)

Visual inspection / physical control

• Inspect easily accessible and visible parts of the system for obvious signs of damage or conditions that may lead to malfunction.
• Check that the lubricant levels and viscosity are correct.
• Determine the exact operating conditions under which the complaint occurs. Consider factors such as vehicle speed, road conditions, ambient temperature, and other factors.
• Compare the driving characteristics or sounds emitted, if any, with a known good vehicle and ensure that no attempt will be made to correct a normal condition.

Intermittent malfunction symptom

Test the vehicle under the same conditions as reported by the customer to ensure that the system is operating correctly.

Increased noise in driving mode

Cause	Method of elimination
Check the transmission fluid and transmission oil levels for correct levels before performing system diagnostics. See "Replacing the transfer case fluid".
Water or contamination in the lubricant Water or contamination in the lubricant causing excessive TCC slip can cause a grinding, growling or groaning sound in the rear differential under light or constant load conditions.	Change the lubricant and flush the transfer case from contaminated fluid.
Weak fastening of the driveshaft mounting bolts	Tighten the bolts if necessary.
Wear of constant velocity joints of the cardan shaft	Replace the driveshaft assembly.
Wear of constant velocity joints of the wheel drive axle shaft	Replace constant velocity joints if necessary.
Incorrect transmission oil in the transfer case	Change transmission oil.
Noise from bearings in transfer case A friction or humming noise increases or decreases depending on the vehicle's speed.	Check the correct fluid level. Top up if necessary. If necessary, if the noise does not stop, repair or replace internal components.
Howling noise from the gearbox in the transfer case The howling noise increases or decreases depending on the speed of the vehicle.	Check the correct fluid level. Top up if necessary. If necessary, if the noise does not stop, repair or replace internal components. The following factors may contribute: Incorrect clearance between gears of the gearbox Wear or damage to gear teeth Increased noise in the gearbox with the main gear assembly Increased noise in the rear differential

Increased noise when coasting

Cause	Method of elimination
Check the transmission fluid and transmission oil levels for correct levels before performing system diagnostics. See "Replacing the transfer case fluid".
Weak fastening of the driveshaft mounting bolts	Tighten the bolts if necessary.
Wear of constant velocity joints of the cardan shaft	Replace the driveshaft assembly.
Wear of constant velocity joints of the wheel drive axle shaft	Replace constant velocity joints if necessary.
Incorrect transmission oil in the transfer case	Change transmission oil.
Noise from bearings in transfer case A friction or humming noise increases or decreases depending on the vehicle's speed.	Check the correct fluid level. Top up if necessary. If necessary, if the noise does not stop, repair or replace internal components.
Howling noise from the gearbox in the transfer case The howling noise increases or decreases depending on the speed of the vehicle.	Check the correct fluid level. Top up if necessary. If necessary, if the noise does not stop, repair or replace internal components. The following factors may contribute: Incorrect clearance between gears of the gearbox Wear or damage to gear teeth Increased noise in the gearbox with the main gear assembly Increased noise in the rear differential

Unstable noise

Cause	Method of elimination
Check the transmission fluid and transmission oil levels for correct levels before performing system diagnostics. See "Replacing the transfer case fluid".
Weak fastening of the driveshaft mounting bolts	Tighten the bolts if necessary.
Incorrect transmission oil	Change transmission oil.

Constant noise

Cause	Method of elimination
Check the transmission fluid and transmission oil levels for correct levels before performing system diagnostics. See "Replacing the transfer case fluid".
Low transmission oil levels	Bad seals or other types of leaks can contribute to fluid levels dropping below normal. See "Diagnostics of transfer case leaks". Add transmission oil to the required level.
Wear of constant velocity joints of the cardan shaft	Replace the driveshaft assembly.
Noise from bearings in transfer case A friction or humming noise increases or decreases depending on the vehicle's speed.	Check the correct fluid level. Top up if necessary. If necessary, if the noise does not stop, repair or replace internal components.
Howling noise from the gearbox in the transfer case The howling noise increases or decreases depending on the speed of the vehicle.	Check the correct fluid level. Top up if necessary. If necessary, if the noise does not stop, repair or replace internal components. The following factors may contribute: Incorrect clearance between gears of the gearbox Wear or damage to gear teeth Increased noise in the gearbox with the main gear assembly Increased noise in the rear differential

Transfer case leak diagnostics

Cause	Method of elimination
Worn, scored or missing drain and/or filler plugs	Install new plugs and tighten them according to specifications.
Worn or damaged primary or secondary shaft seal	If necessary, replace the secondary shaft seal.
Cut or damage to the secondary shaft housing O-ring	Replace the O-ring if necessary.
Wear of internal shaft seals Wear or damage to the internal shaft seals can be detected by fluid leaking from the vent area at the bottom of the cover.	Replace seals if necessary.
Cut or damage to the O-rings where the transmission and final drive assembly meet and the transfer case	Replace O-rings if necessary.
Porosity or leakage of sealing surfaces of boxes or crankcases	Replace the transfer case assembly if it cannot be repaired.

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