Hi, I'm UK based and have a 2000 540i M Sport with what is possibly a transmission / auto box problem. There is an intermittent noise / grinding sound coming from what sounds like the near side (left in my case) rear - initially I though it might be a wheel bearing however it does appear to be linked to the gearbox - it feels like it's dropping between gears and the engine "hunts" very slightly. It tends to happen between 40 & 50 MPH and less at higher speeds. Does anyone have any ideas what it might be?
Transmission problem? on 2000 BMW 540i
There are so many possibilities when it comes to automatic transmission shifting problems. I would start with checking the fluid level and condition, then I would look through the technical service bulletins. We have a good company in the states, alldatadiy.com where you can get this info, or in the EU there is great company, Autodata, but I'm not sure if they offer the bulletin info or not. I would want to make sure the transmission module had the latest software, but if the transmission is noisy, then you may have mechanical issues.
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I believe its the same problem I was having. The car would vibrate between 30-50 mph and once downshifted from D to 4 it would go away. At highway speeds it would "hunt" up and down with the transmission shifting at the right speeds. Finally did my own research and diagnostic and took a chance and replaced the torque converter and the problem disappeared. Was told by a BMW tech that the best thing was to replace the transmission.
In addition, the rpm surge either up or down was in the 250-300 rpm while "hunting".
This is the torque convertor clutch slipping while trying to engage. It is best to replace the transmission based on the cost of torque convertor vs new trans and torque convertor are very close. Plus all the metal debris from the slipping torque convertor clutch is now circulating through the trans and the trans failure will be following at some not to distant point in time. That's my opinion as a bmw tech and owner who experienced the same issue.