BMW X Drive Series E Transfer cases

Taking into consideration the standard drives, we can differentiate two types of transfer cases. There are transfer cases that are chain driven. Usually, the BMW use these for their,, off-road vehicles”. Furthermore, we also have to calculate with the gear driven transfer cases, which is mostly used for passenger cars. 

What is our common and most sensitive part?

The answer is the Clutch. The clutch can be found in both types of transfer cases as a separate unit but it has a crucial role in distributing and controlling the proper amount of torque to the right direction.

As the illustration shows, the torque is going through the friction plates. If the friction plates and the switch handle are dysfunctional that will result of shaking transfer case and may disable the vehicle. 

Why is this problem occurring?

It has a simple reason: the friction plates are wearing out. We can increase the lifetime of the friction plates with proper lubrication and regular oil change in the system. Naturally, there is a normal level of wear-and-tear and abrasion of the friction plates but it can be readjusted by the electric motors in the transfer cases, which is also sensitive part and not guaranteed for a lifetime. We can also find the oil pump in both types of transfer cases and we think that the function of this part is obvious for everyone.

The main reason of breakdown may be the clogging in the oil pump by the metal filings going into it. As a result of this, the pump will not be able to provide proper lubrication for the clutch of the transfer case, which will cause the abrasion and damage of the clutch parts, such as the pin-bearing or the row of the friction plates. The clutch will not be able to close properly and would cause slip that the passengers will feel like shaking.

Let’s move forward: To reach the optimal closure of the clutch, we need a clutch bell to provide something to the friction plates to catch.

In both transfer cases, the movement of the axles and gears is ensured by ball-bearing and tapered bearings. Typically, they can stand for a long run but again the proper use of oil is also a crucial part of this. If we can find the sufficient amount and quality of oil in the transfer case, we only have to focus to keep it inside the system. We can easily achieve it with the appropriate sealing and rings.

To conclude the experiences listed above: These transfer cases can be easily and perfectly repaired because it is a twenty years old proven technology. The long-term success is guaranteed by using high quality parts and a little bit of concentration.