How To Tell If A Transfer Case Is Failing

A GM transfer case should last at least 100,000 miles. Transfer cases are built to be workhorses, but they may fail eventually. When a transfer case fails, one of these two scenarios can happen:

1. If you have a part time 4WD, the transfer case may not want to shift into 4WD. That can be a  big problem when you’re a situation where 4WD is necessary.
2. If you have an AWD, the transfer case is a full-time part within the drivetrain. When the transfer case fails, other parts within the drivetrain can get damaged.

Either way, you want to diagnose the issue as soon as possible. This diagnostic guide will walk you through the process.

Telltale Signs Of A Bad Transfer Case

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Do you have a hunch that your transfer case either has failed or is on the brink of failure? It helps to see if you’ve noticed any of the following symptoms:

• Grinding noise while shifting gears
• Difficulty staying in 4WD
• 4WD not engaging or disengaging
• Grinding, growling, or humming noises that change with vehicle speed
• Illumination of the 4WD warning light in the dash

These symptoms are good indicators that something is wrong with your transfer case. That's not always the case, though. It could mean that there's something wrong with the differential, driveshaft, or another part. That's why you want to diagnose the issue before moving forward.

Sometimes It’s The Adapter That Failed

There are many things that could go wrong with a transfer case. For example:

• Low fluid level
• Loose chain
• Bad bearings
• Damaged gears

Sometimes the transfer case is fine, but the adapter has failed. Some vehicles have an adapter which is a metal ring that serves as a connection between the transfer case and the transmission. If your truck SUV has one, check the adapter for cracks and other kinds of damage.

If the adapter is bad, you can replace only that part instead of the whole transfer case. A replacement adapter is much cheaper than a new transfer case. You can order a genuine OEM GM adapter from us for wholesale pricing.

Checking Your Transfer Case

Image Credit: spelunkerd

The best way to determine if your transfer case has failed is to slide underneath your vehicle and give it a visual inspection. You want to look for:

• Metal shavings in the transfer case fluid
• Any visual damage on the transfer case (such as cracks or dents)
• Any leaks

To do this:

1. Park your vehicle on a flat and even surface.
2. With a flashlight, closely inspect the transfer case for:
   1. Leaks
   2. Cracks
   3. Any other kinds of damage
3. Grab a container. Remove the drain plug on the transfer case and then let the fluid drain out.
4. Examine the fluid for any metal shavings. If you find metal shavings, there's an issue within the transfer case. You'd have to take it apart to find out what the issue is, but it's just easier to replace it. The issue could be a variety of things:
   1. A component within the transfer case may have broken.
   2. The transfer case may not be getting enough lubrication.
   3. It may have simply worn out.

Do you have any questions about diagnosing your transfer case? Or do you need help finding the right replacement part for your GM? Either way, you’re welcome to contact us.