The transfer case is the drivetrain part that transmits the power from the transmission system to the rear and front axle for wheel spinning. It contains fluid inside the gearbox for lubrication of its components.
BMW X5 transfer case problems include loss of fluid pressure, growling and humming noise, four-wheel drive warning lights, issues in gear shifting, damaged seals, corrosive parts, and vibrations during acceleration.
A faulty transfer case does not allow you to shift the gears quickly because of loss of power. I tried to shift from 6th gear to 5th, and it took a lot of time to engage the shifter.
| Problems | Solutions |
| Loss of fluid pressure | Remove the fluid plug and add the fluid |
| Growling and humming noise | Replace the snip ring or bearing |
| Incorrect power distribution | Replace broken chain or gear |
| Four-wheel drive warning light | Take short breaks while driving to cool transfer case parts |
| Issue in gears shifting | Regular inspection of transfer case parts |
| Damaged seals | Replace outer seal |
| Corrosive parts | Lubrication of metal parts |
| Vibrations during acceleration | Correctly center the transfer case yoke |
Loss of fluid pressure
The transfer case transfers the power from the transmission to the rear and front axle for the movement of tires. It is present in BMW vehicles that have four-wheel and all-wheel drive features.
This component also contains the fluid to reduce the friction between their parts and smooth functioning. Moreover, its fluid also protects the gearbox from heat-related damages.
It dissipates the heat that is produced because of their moving parts. You can face issues in this part because of loss of fluid pressure.
These cannot function properly because of low levels of fluid. Low levels of fluid do not allow their smooth movement and transmission of power according to selected gears.
Fluid level decreases because of lack of maintenance and age-related wear and tear of their components. My friend also faced the same issue, and he saw fluid under his BMW X5.
He became worried and thought that it was a motor oil. He checked the engine components, but their seals and gaskets were fine. He realized that fluid was present near the location of the transfer case, and he also faced an issue while shifting gears.
Growling and humming noise
You can hear growling, humming, and whining noises because of bad transfer case components. Noise production depends on the severity of the problem.
You should not drive your vehicle while ignoring these noises because it can lead to severe damage to the drive train and transmission components.
You can hear the noise because of the grinding of metal parts. Metal comes in contact with metal material, and you can hear noises because of their friction.
The issue comes because of the loss of transfer case fluid and lack of lubrication between metal parts. Moreover, you can hear humming and grinding noises because of loose bearings, damaged gears, and bad snip rings.
Use jacks to raise your SUV and inspect the drivetrain components. You should replace the damaged snip ring or bear with a new one for efficient working of four-wheel drive.
Incorrect power distribution
Sometimes, it does not distribute power equally to the rear and front-wheel drive, which can increase the skidding chances on snowy and unpaved roads.
You need equal power on all wheels for their rotation at the same speed to decrease slipping chances and maintain traction. Incorrect power distribution issue comes because of low fluid levels that do not allow the gearbox and chains to engage properly for power transmission.
Broken gears and chains do not provide sufficient and equal power to the rear and front axles. You can also face problems because of their faulty electric components, including wiring and control modules.
It is necessary to take guidance from an expert mechanic if you face the problem of loss of wheel traction while moving on snowy roads.
Four-wheel drive warning light
The main function of the transfer case components is to split the power between the rear and front axles. Sometimes, their components overheat and stop functioning.
The issue usually comes during long driving without any break. Engine and transmission parts also heat because of their over functioning.
You can see the four-wheel warning light on the cluster screen. The warning gives the message that you cannot engage the 4WD because of the overheating of transfer case components.
A warning light comes on screen to ensure the safety of the driver and passenger, so you should drive carefully on slippery and unpaved roads.
It shows that you cannot engage or disengage the 4WD to gain traction and reduce the chances of wheel skidding. My friend faced this issue while driving on a highway during a long trip.
He called and told me that the 4WD warning sign was not going out from the screen, and he could not engage the 4WD. He had difficulty driving because it was a rainy day.
I recommended my friend to stop for a few minutes and allow the drivetrain components to cool. He stopped there for about 10 to 15 minutes and started his BMW X5 again, and the issue was resolved.
Issue in gears shifting
You can face issues in shifting gears because of low levels of fluid in transfer cases or leaking fluid. Leaking fluid does not allow you to shift your vehicle from higher to lower gears and vice versa.
Moreover, you cannot keep the 4WD activated because failure of their components causes sudden power loss. It becomes difficult for you to stay in 4WD while moving on slippery roads.
You can reduce the risk of damages with regular inspection and timely fluid changes.
Damaged seals
It contains an outer seal for the protection of metal parts. In addition, seals also keep the fluid inside for lubrication of metal parts.
The outer seal is beneficial for keeping the metal lubricated by keeping the fluid inside.
Broken seals cause leakage of fluid and damaged parts. Metal parts cannot move smoothly because of insufficient levels of lubricating oil.
Low levels of lubricating oil also cause overheating of their components. Outer seals can break because of age-related deterioration and exposure to high temperatures.
You have to replace the broken seal with a new one to decrease the risk of leakages and keep the metal parts lubricated for their efficient functioning.
Corrosive parts
Transfer cases contain metal parts that can corrode because of exposure to road elements. In addition, the chances of their rusting increases because of corroded undercarriage.
You can also face corrosion issues because of the insufficient lubrication of their components. It is necessary to lubricate their parts regularly to protect them from road salts and moisture exposure.
Moisture and road debris can also contaminate their oil and cause issues in the smooth functioning of their parts. You have to replace the contaminated oil with a new one via a drain plug.
Vibrations during acceleration
Many people complain that they feel the vibratory motion of their BMW X5 during acceleration because of faulty transfer case components.
You can feel vibrations because of drivetrain components that do not provide sufficient power for wheel movement.
The vibration issue comes because of the poor alignment of the transfer case yoke. You can face problems when these are slightly off-centered from their exact position.
The issue comes because of regular driving and physical impacts. It is better to take your X5 to the expert dealership for centering the case yoke and decrease vibratory movements while accelerating.
I also faced this issue while starting my vehicle, but I checked the engine parts and thought the acceleration issue usually came because of the engine malfunctioning.
Engine parts were fine, then I inspected the transfer case, and the case yoke was off-centered.
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