Transmission Reliability

[JCL]

My thoughts on transmission failures have been included in (many) previous threads, some of which Quick has linked in this thread.

A couple of thoughts:

Why does everyone seem to think that changing the transmission fluid will extend the life of the automatic transmission? Documented failures here haven't been due to burnt (overheated) fluid, but rather due to torque converters, electronic sensors, reverse clutches, software, etc. None of those would be improved by changing the fluid, and if changing the fluid dislodges any sediment then in fact changing it would hasten those failures.

If anyone is buying an X5 planning on 500 k km service life, they are dreaming IMO. The engines will probably be fine. The software and electronics, however, will sideline the vehicle long before the engines wear out.

BMW have never promised that the transmissions will last your lifetime, or that they will last the vehicle's lifetime. They have said that the fluid will last the transmission's lifetime. So far, that has been pretty accurate, given the lack of failures attributable to fluid breakdown.

I am with Wagner. I have purchased five BMWs in recent years, and didn't keep any of them more than 80,000 km (50,000 miles). Personally, I sell them after a few years so that kids and others can buy them used, and then spend their money on nuisance repairs. I buy BMWs new because they aren't expensive for what I get. If BMW spent more money making the transmission good enough to last 500,000 miles, I wouldn't buy the cars in the first place because they would be too expensive. They have an appropriate level of durability for the price point.

We are picking on BMW a fair bit in this thread, but they aren't even BMW transmissions. They are built by ZF and GM, two companies that makes some of the best automatic transmissions in the world. Sure, BMWs will be obsolete in a few years, same as most other brands. That is the price we pay for the constant consumer demands for more power, lower emissions, more electronic options, more technology, and so on. Does anyone else remember driving vehicles that didn't have reverse cameras, PDC, DSC, 8 speed automatics with lock up torque converters and adaptive shift algorithms? It wasn't that many years ago, yet people are still expecting the same reliability they got from cars that did not have those features.