The transfer case is one of the most important components that distinguish all-wheel drive (AWD) and four-wheel drive (4WD) vehicles. Driving all four wheels provides superior traction, resulting in improved performance in challenging terrain. This is made possible by the transfer case, which allows power to be transferred to both the front and rear wheels.
When you have a faulty transfer case, you’ll find that you may have difficulty or are unable to switch to AWD or 4WD.
In this article, we’ll discuss some of the symptoms you may experience when this component fails.
The transfer case is supposed to last the life of the vehicle—but that doesn’t always happen. Here are some of the most common signs you may encounter when you have a bad transfer case:
One symptom of a bad transfer case is when you have trouble shifting between gear ranges. Although the issue can be caused by something simple, such as a low fluid level or damaged linkage, it typically indicates an internal transfer case failure.
Before assuming something is wrong, however, make sure that you’re following the directions (in your owner’s manual) for operating the transfer case. In many instances, before shifting into four-low, the vehicle must be stopped and the transmission placed into neutral.
Otherwise, you’ll hear a grinding noise when trying to shift gears.
Note that while some transfer cases are controlled by the body computer, transfer cases on most modern vehicles are electrically-switched. As such, some vehicles may exhibit different symptoms.
Another common problem is a transfer case that pops out of 4WD. The issue can be attributed to outside influences (e.g., a problem with the differential or driveshaft) or it might be due to an internal transfer case concern.
There are many reasons why a vehicle’s 4WD system won’t engage or disengage. The issue could be due to anything from a faulty shift mechanism on the front axle to an electrical fault in the control system.
It’s also possible that the transfer case has internal problems.
There’s only one reason why there’s a greasy puddle building up underneath your car—there has to be a leak somewhere.
And that somewhere could be the transfer case.
Verify that the leak is coming from the transfer case by jacking up your car and visually inspecting it. You should easily see it at the rear-end part of the transmission or transaxle assembly.
If a leak is gradual (and they often are), you may not see a puddle, but over a period of time, the transfer case can become dangerously low on oil, leading to the destruction of internal components. This takes longer than a manual transmission to show up because transfer cases have an oil pump—manual transmissions typically don’t.
Another telltale sign of a problem in your car is the presence of weird noises that weren’t there before. Abnormal noises can be bothersome, and they almost always indicate that bigger problems are right around the corner.
If you hear a grinding, growling, or humming noise that changes with vehicle speed, it might be coming from the transfer case. The root cause could be low fluid level or a mechanical problem, such as a loose chain, bad bearings, or damaged gears.
Some vehicles have a “service four-wheel-drive” message (or something similar) that pops up on the dash when there’s a problem in the system. Other vehicles will simply keep the 4WD light illuminated continuously to indicate a problem, which could be a bad transfer case.
Typically, a transfer case will fail due to a low fluid level (caused by leaks), lack of maintenance, or regular wear from use.
It’s important to address fluid leaks right away (as soon as you discover one) to prevent internal transfer case damage. Changing the transfer case fluid on a regular basis is also important. You can find the service interval for your vehicle’s transfer case in the owner’s manual.
The transfer case is a part of your vehicle’s drivetrain, as is the transmission—and they both have their respective functions. Despite this, the symptoms of transmission failure can mimic those of a bad transfer case. This can sometimes result in confusion for vehicle owners who are attempting to fix their car themselves.
To avoid any confusion, it’s a good idea to have a professional diagnose your vehicle if you suspect a transfer case problem, as they would have the proper tools (and years of experience) to better assess your vehicle and its underlying issues.
Note that bad four-wheel-drive locking hubs can be construed as a transfer case problem as well and can, if they fail engaged, damage the front differential.
As an interesting side note, some older transfer case systems, such as on early 90s Fords, will, when they illuminate the “Low Range” indicator, cause the Powertrain Control Module to use a different shift schedule, causing it to shift through all its gears at very low speeds. The point is that something as simple as a blown fuse (killing power to the Low Range light) can cause this issue.
Some older transfer case systems, such as on early 90s Fords, will, when they illuminate the “Low Range” indicator, cause the Powertrain Control Module to use a different shift schedule, causing it to shift through all its gears at very low speeds.
–Richard McCuistian, ASE Certified Master Automobile Technician
There are instances where a catastrophic transfer case failure can damage other parts of your vehicle, including the transmission. It’s always a good idea to address any known issues with your vehicle as soon as possible to avoid additional problems.
Some Ford Trucks had issues with their electronic modules that would randomly put the vehicle in four wheel drive at highway speed, causing tremendous destruction. There was a dealer program concerning this, so check your VIN at the Ford dealer to see if your vehicle is at risk.
As previously mentioned, the transfer case is found on vehicles with AWD or 4WD capability and is integral in allowing drivers to switch to these modes of operation.
A typical 4WD transfer case is found at the rear of the transmission. It is powered by the transmission output shaft and operates much like a secondary transmission.
Most 4WD transfer cases have four modes of operation: two-high, neutral, four-low, and four-high. Because the driver only engages the 4WD when needed, this type of system is called “part-time” four-wheel drive.
The desired gear range may be engaged with a lever, engine vacuum, or onboard electronics.
AWD systems distribute power to all four wheels without any driver input. Many modern SUVs have AWD and a front-wheel drive-bias layout. Vehicles with this design have a transaxle instead of a transmission.
The transfer case mounts to the side of the transaxle and distributes power to the rear differential and one of the front CV axles. You may also hear people refer to this type of transfer case as a power transfer unit (PTU) or something similar.
These systems have what is called a “viscous coupling” in the system. Without it, full time four wheel drive wouldn’t be possible.
Think of how part time four-wheel drive requires all four tires to be exactly the same size and how the part time system will experience “driveline windup” if operated on a flat, dry surface with the four wheel drive engaged.
There are also some vehicles that have AWD and a rear-wheel drive-bias layout. With this design, the transfer case is much like one found in a 4WD vehicle. The primary difference is that the transfer case doesn’t have multiple gear ranges for the driver to choose from (operation is automatic).
That’s why this type of setup is sometimes referred to as full-time 4WD.
There are also electronically activated automatic four wheel drive systems that only engage when needed and cannot be controlled by the driver.
Driving around with a bad transfer case is a disaster waiting to happen. The transfer case plays a crucial role in your vehicle’s drivetrain system, and if it fails, it won’t be long before issues arise in your vehicle’s overall performance. This can make driving dangerous, so don’t put off replacing it. Fortunately, getting a new transfer case is a breeze with CarParts.com.
Use our vehicle selector to view replacement transfer cases that are compatible with your vehicle. Enjoy fast and reliable shipping, thanks to our on-hand products and strategically located warehouses across the US. Place your order today, and we’ll have it delivered to your doorstep in as fast as two business days.
Don’t wait for the worst-case scenario to unfold before replacing your faulty transfer case. Shop for a new transfer case from CarParts.com today.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.
View Comments
I have a jeep liberty 2003 that has never given me any problems regarding the transmission. However after putting the vehicle into part time and then taking it out, about ten miles later after slowing down from 70mph to 30mph a weird grinding and winding noise started coming from right under the vehicle. Afterwards the vehicle would jolt after i accelerated it and would have trouble changing gears to the point where when I went about 40 mph the rpms would be at around 4000 and only go higher the more i accelerated. I suspect something to do with transfer case, any other help would be appreciated.
Hi Robert,
An increase in engine RPMs without an increase in vehicle speed usually indicates a slipping transmission. I would look into that, first.
Hi I have a 2008 Toyota Sequoia everytime I switch to 4HI I hear a grinding noise when I drive. When I switch to 4LO there is a light that blinks and all I hear is a beeping, I drive around in 2WD. Someone told me I should replace the transfer case fluid and see if that works out. Do you have any experience with this problem and how I can solve this?
hello, i have a mitsubishi airtrek turbo year 2005, the car seems to be shifting roughly from park to reverse or drive, seems normal in park and neutral, could it be the t case that cause the problem, it made a sound like a metal hitting sound. it only happen when shift to drive or reverse, other than that it jerks sometime while in drive mode, other than that seems fine.
Hello,
That sounds more like a problem with the transmission. I would begin your troubleshooting process there.
Hey, i dont mean to be a bother... but ive ran into a problem with my 5.7L 98 tahoe. i heard no symptoms of something going out, until i tried it one day, and starting it... just to find the neutral light on red, and 4lo, and 2hi lights on at the same time! ive replaced the actuator, and buttons. it fixed nothing, so as a test i picked a new transfer case motor, and plugged in in, but havent fully installed. i heard in an article that it should make a noise, or show a sign of the light changing after the harnesses are in, but it shows the same. should i continue dropping the drive shaft, and replacing the transfer case motor, or is it seeming like it could be something else?!? thanks for reading if you got this far!
Hello, I have Hummer H3 3.7, last week I removed transfer case and after istallation I forgot to put the oil back, so I drove without oil about 500 miles, i put the oil again now, it has no clicks or something like it but now it slipping in 4 and 5 gear, can it be a transfer case or thats a transmission problem?
I have a 2002 Hyundai Sante Fe just had the cv axles and transfer case changed last week at the repair shop. Picked the car up from the shop Fri, put car in reverse it had a rough idle but it was almost empty of gas. Put in fuel and it smoothed out. Have driven the car less than 50 miles since I got it out of shop and the power steering reservoir is now leaking and the car has a bad misfire and not shifting gears correctly Car had no problems with misfire or rough idling or shifting problems until change out.
Hi Brenda,
The shop would have had to disconnect some sensors while replacing the transfer case, so it's possible the issues you're now experiencing are related to the repair. It's also possible that it's just an unfortunate coincidence. I would contact the shop and ask them to take a look.
I have a 2008 jeep wrangler I went to take it on the beach and at times I would press on the gas but the tires did not move. Drives fine on the road and i don't hear any weird noises.
Hi Ryan,
Is the vehicle essentially in neutral or is the four-wheel drive just not engaging?
06 bmw x3 2.6 101,502.22 miles 4x4 light came on after traveling down steep hills and curves. brake light went off. 4 x 4 stayed on went in reverse car hard to steer and sluggish. parked car , next dayleaned into car , no foot on break and started with key. car lunged forward a foot easily and started. no lights no problems. 4 days later 4x4 dash light on and rev slugish . please help
Hi Marcia,
When the service all-wheel drive light pops up on the dash, that means the onboard system has detected a problem with the all-wheel drive system. The system will also store one or more corresponding diagnostic trouble codes in its memory. Retrieving those codes is the first step to finding out what's wrong with the car.
Unfortunately, inexpensive OBD code readers will not retrieve the codes from the all-wheel drive system. So, I suggest taking the vehicle to a professional with the necessary equipment to retrieve the codes and complete the diagnostic process.
I have a 2014 gmc sierra. And my truck just all of a sudden got stuck in 4x4. I had to pull the TREC 4x4 fuse to put transfer case module to sleep to disengage my 4wd. Is that a bad transfer case module doing that?
Hi Larry,
I'm assuming your transfer case has the shift lever on the floor instead of the dial on the dashboard?
I have a 03 duramax with an lb7 .my truck dies as soon as I put in in reverse. Will low transfer case oil be a cause of this problem? Please help
Hi Joe,
No, the problem you're experiencing would not be caused by a low transfer case fluid level. The issue is likely an engine performance problem, causing the vehicle to stall when the transmission is placed into gear. Putting the transmission in gear changes the load on the engine.