Transfer Case Leak: What Are the Causes and Solutions?

A transfer case leak can damage the gears of a vehicle, making it difficult to start or leading to stalling. The causes of this phenomenon can be varied and so are its solutions.

Transfer Case Leak

This article will discuss what a transfer case is, the various incidents that can cause the leakages, and how to solve them. We will also discuss how to prevent the case from leaking and answer some pertinent questions on the case.

What Is a Transfer Case Leak?

A transfer case leak is a problem that occurs when the transfer case fluid seeps out of the shaft, failing to lubricate its components properly. When it is not fixed in time, the leak can affect the gearboxes, making it difficult to change gears in both manual and automatic transmissions.

What is a transfer case? A transfer case is simply a component of the powertrain that sends power from the gears through the drive shaft to the front and rear axles of all multi-powered axle vehicles. Transfer cases make use of different systems including gears, hydraulics or chains.

A transfer case leaking oil or a transfer case leaking transmission fluid would cause the components to rub against each other, resulting in wear and tear. In time, the components would be damaged and the vehicle can’t switch to four-wheel drive.

– Causes of Transfer Case Leak

Transfer case leak happens when the gasket is broken, allowing fluid to seep through. The gasket is a sealant designed to prevent liquids from trickling out or prevent two different fluids from mixing up and hampering the work of the engine.

Causes of Transfer Case Leak

The work of the gasket is essential to engine performance, however, it can become brittle over time and break. If it is not replaced in time, the fluid from the transfer case will seep out of the shaft and make it hard to change the gears. Whenever you notice fluid coming out of the transfer case, it means the gasket is broken and needs to be replaced.

The best person to replace a gasket is a professional mechanic who will check where the leak is coming from and change it accordingly.

– Fixing a Transfer Case Leak

The primary thing to do is to check the level of the fluid in the case. If it is low, then you need to top it up to see if there’s a fluid leak. Once there is, check the gasket seals (especially the output shaft seal) to see if they are broken and replace them with new ones.

There are two seals: one in the front (input shaft seal) and the other in the rear of the case (output shaft), thus you’ll have to determine whether one or both of them should be replaced. To check if the fluid leak is from the front seal, detach the driveshaft and the plate that covers the seal. Once the seal is bare, check for cracks or breakages and if you find one, take out the old one and replace it with a new one. Ensure that you use a sealant to glue the gasket tightly so it doesn’t leak.

However, if you check the front seal and there’s no leakage, then inspect the seal at the rear. To do that, take out the driveshaft and detach the transfer case and check the rear seal for cracks. If you find any, then replace the old one with a new one and seal it to make sure it is airtight. You can also use a transfer case leak sealer, but the best method is to replace the entire seal.  

– Various Signs of a Leaking Transfer Case

When the vehicle shifts from two-wheel to four-wheel drive without the driver activating it, this is a sure sign that the transfer case is leaking or damaged. This sign can be tricky in a car with a part-time four-wheel drive system because the switch from two-wheel to four-wheel is done without the driver’s intervention.

Various Signs of a Leaking Transfer Case

However, if there’s no bad weather or slippery or muddy roads and the vehicle switches from two-wheel to four-wheel drive, then chances are that the transfer case is leaking or broken.Also, if you experience difficulty in shifting the gears, then the transfer case could be leaking. This is because the fluid in the case is to enable the smoothing shifting of gears.

Therefore, if it reduces in quantity, the internal components begin to rub against each other, thereby increasing friction. The grinding of the internal components can cause noises beneath the car, which is another sign of a leaking transfer case.

– Avoiding Transfer Case Leaks

To prevent leaks from the transfer case, make sure you service the case periodically, and this includes checking the sealants and the oil level to detect any oil leak. Also, change the fluid regularly because old dirty fluid can cause the seals to break. Use the right kind of fluid because transfer cases come in different types and each has its type of fluids, thus using the wrong fluid could cause problems for the sealants and the case itself.

Also, avoid driving on bad terrains that can hurt the transfer case which is below the car. If bad roads are unavoidable, then it is best to slow down so that the effect of the rough terrain on the case is greatly minimized.

– Driving With a Leaking Transfer Case

It is dangerous to drive with a transfer case that is leaking because doing so could damage the transmission. When you see signs of leaks in the transfer case, have it replaced immediately.

Driving With a Leaking Transfer Case

Transfer case leak repair cost is between $225 and $270 without labor costs. Labor costs vary between $175 and $220, while the parts go for $55.

– How the Transfer Case Works

The transfer case is usually found behind the engine of a four-wheel or an all-wheel drive vehicle. It consists of two sets of gears; one set is connected to the engine while the other is to the axles. The two sets of gears rotate at different speeds, which provides enough torque to turn the wheels. Due to the work of the gears and chains in the transfer case, you can switch between two-wheel drive and four-wheel drive by engaging or disengaging the front wheel/axle.

How the Transfer Case Works

This prevents the vehicle from slipping because if one or two of the wheels lose traction, more torque is transferred through the transfer case output shaft to the wheels which have traction. The option to switch from a two-wheel to a four-wheel can be done manually or automatically.

Some new vehicles are equipped with part-time four-wheel drive systems that can sense when a vehicle requires four-wheel drive and adjust accordingly. However, older models don’t have that luxury, thus the driver would have to engage the front wheel manually.

Can a Transfer Case Leak Cause Fuel Injector Problems?

A transfer case leak can contribute to fuel injector problems. If the transfer case seals fail, fluid may enter the engine compartment, posing a risk to the fuel injection system. It’s important to watch out for leaking fuel injector warning signs such as decreased fuel efficiency, rough idling, or the smell of fuel. Promptly addressing any transfer case leaks can prevent further complications with the fuel injectors.


This article has discussed the causes of leaks in transfer cases and how to fix them.

Here is a recap of all that we’ve discovered:

  • Transfer case leak happens when the gasket is broken, allowing the fluid to seep out of the case.
  • Transfer case leak symptoms include difficulty in changing gears, vehicle switching from two-wheel drive to four-wheel drive, and noises from the transfer case.
  • To fix a leaking transfer case, replace the old sealants with new ones and that’ll do the trick.
  • To avoid cases of transfer leaks, don’t drive on rough bumpy roads and if you have to do it, then do so gently.
  • Regularly check the level of the fluid in the transfer case and when it is low, look for leaks around the case.

Transfer cases are essential components of vehicles, therefore they should be checked regularly to ensure they are working well.

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