GMC 4×4 Parts

Difficulty staying in four-wheel drive (4WD)
One of the common problems you’ll notice when the transfer case fails is difficulty staying in 4WD. However, the issue can result from a host of other problems like the driveshaft or differential issues. It might also be an indicator of an internal transfer case problem.

Four-wheel drive (4WD) not engaging or disengaging
There are many reasons for 4WD to be disengaging or not engaging. The root cause ranges from electrical faults in the control system to defective shift mechanisms. The transfer case may have an internal problem.

Embarrassing Humming, growling, or grinding noise
A common sign of a problem on the vehicle is a strange noise that isn’t present before. Awkward and annoying noise can be bothersome, and it may indicate issues around the corner. If you hear a humming, growling or grinding noise that increases as you accelerates the vehicle while driving down the road, chances are, it’s coming from the transfer case.

Puddle buildup under the transfer case
The only reason for a greasy or oily formation under the vehicle is a leak around that area. And the oil leak can be coming from the transfer case. Visually inspect if the leak is from the transfer case by sliding under the truck. The transfer case is located at the rear-end of the transaxle or transmission assembly.

Gear shifting issues
Another common symptom of a bad transfer case is gear shifting issues between gear ranges. However, the root cause might be a damaged linkage or low fluid level. When having issues with gear shifting, before assuming you have a problem, ensure you’re following directions in the owner’s booklet for how to operate the transfer case.

Illuminating four-wheel drive warning light
Some vehicles are equipped with ‘4WD service required message’ (or similar message) that will come on the dashboard when there’s an issue in the system. In contrast, other vehicles will blink continuously to indicate a problem within the system.