If you have a four-wheel drive or an all-wheel drive car, you have more than just the engine and the transmission to worry about. You also have a transfer case, which is responsible for sending power from the transmission to all four wheels via drive shafts. If your transfer case fluid is low, there’s a problem that should be repaired before you can safely drive.
How this system works:
A transfer case does exactly what the name implies – it transfers power from the transmission to the wheels. However, it will work differently depending on the type of vehicle you drive. If you drive a four-wheel drive truck, then the primary wheels are driven by the driveshaft and the transfer case really only comes into play when you engage four-wheel drive mode. However, if you have an all-wheel drive vehicle, or an all-time four-wheel drive system, then the transfer case will be used at all times (because all four wheels must work at once, at all times).
The transfer case mounts to the end of the transmission, and a shaft extends from the transmission into the transfer case. Inside the transfer case, there are internal forks and gears that are responsible for transmitting the rotational power of the transmission to two other drive shafts – one going to the rear differential, and another going to the front differential. Within each differential, rotational power is split again, and redirected at 90 degrees to each wheel.
Common reasons for this to happen:
Leaking Input Seal at Transmission: If you’re experiencing low transfer case fluid, one of the first possible problems to consider is the input seal on the transmission side of things. Over time and through normal wear and tear, these seals will degrade, eventually letting fluid seep out.
Leaking Output Shaft Seal Rear: Another potential problem is the output shaft seal where the rear drive shaft attaches to the transfer case. Like the input seal on the transmission side, this one can also wear to the point that it begins to leak.
Leaking Output Shaft Seal Front: You have one other potential seal that might be leaking. This one is located where the front drive shaft connects with the transfer case. Like the other two we’ve mentioned, this seal will eventually degrade and begin to leak.
Leaking Vent Hose: While unlikely, it’s possible that you’re losing transfer case fluid from the vent hose.
Failed Speed Sensor Gasket: If your transfer case is equipped with a speed sensor, it’s possible that you’re leaking fluid around the sensor (the seal has failed).
Leaking Transfer Case Gasket: The transfer case gasket is a lot like an oil pan gasket in that it will eventually degrade to the point that it begins to leak fluid (all gaskets and seals on your vehicle are subject to wear, leakage and eventual failure).
What to expect:
A top-rated mobile mechanic will come to your home or office to inspect the leak from your transfer case, as well as the condition of all seals and the level of your fluid. The mechanic will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done:
The mechanic will inspect the transfer case first to determine the location of the leak. It may be necessary to clean old fluid from the transfer case and then test drive the vehicle to determine the actual source of the leak. The mechanic will also check the level of fluid.
How important is this service?
If your transfer case is leaking, the internals are in danger of experiencing high heat and friction. Just like your differentials and your transmission, the moving parts within the transfer case must be lubricated properly at all times, or damage will result (depending on the setup of your vehicle, damaged transfer case components could leave the vehicle unable to be driven). One of our professional mechanics can inspect your transfer case, determine the point of the leak, and repair the problem.