The transmission on your BMW is very intricate and one of the most complex components of your BMW. A replacement transmission can cost more than the value of your entire vehicle.
Nowadays, many dealers and repair shops offer a transmission flush as a service to prolong the life of your transmission. This is a highly profitable and efficient way of generating revenue, and has gained popularity because of this. However the problem with this service is that the dirty filter that has collected all the debris through normal wear and tear over tens of thousands of miles remains in the transmission, so essentially you are putting new fluid in a dirty transmission (similar to changing your oil but not changing your oil filter). Over time this filter becomes more restricted and reduces the correct amount of flow of transmission fluid that your transmission requires (similar to a coffee filter being used a second time). Furthermore, many repair facilities attempt to increase profits and use a generic fluid that the manufacturer of the transmission does not recommend.
At Bimmer Connection, we recommend a proper transmission service to adequately maintain your transmission. During this service, the transmission is drained, the filter (which is incorporated in the transmission pan on many models) is replaced, the transmission pan gasket is replaced, the transmission pan is inspected for any signs of internal damage, and the transmission is refilled with the proper amount of the correct fluid the manufacturer uses.
One of the worst fears BMW owners may have is seeing the transmission warning light come on, and rightfully so since transmissions can be so costly to replace. Many times however, the transmission is repairable. As a general method of operation, dealerships don't disassemble transmissions since the individual parts aren't available to them through BMW, leaving a transmission replacement as the only available option. Another option many customers explore is to buy a rebuilt user transmission. However the control module integrated with the valve body of the transmission can not be reused, therefore a new one must be purchased, which may cost thousands on top of the cost of a rebuild transmission.
At Bimmer Connection, your transmission can be diagnosed and your transmission may be repairable without taking on the excessive expense of a transmission replacement. An initial diagnosis may reveal whether or not your transmission is repairable, and if so the transmission can be checked for a repairable solution, not replacement.