BMW 540i transmission unexpectedly jumps into neutral after valve cover replacement on BMW 540i

Some BMW 540i owners report experiencing transmission issues, such as the transmission unexpectedly jumping into neutral after replacing the valve cover. This problem may arise if the spark plug tubes are overlooked during the replacement, leading to oil leaks that can affect transmission performance. Additionally, owners may encounter transmission problems related to the valve body, which could result in complete transmission failure. Diagnostic challenges can include checking for contaminated fluid and determining whether to repair, rebuild, or replace the transmission. Furthermore, if the service engine soon light activates alongside engine downshifting and high RPMs, it may indicate underlying engine issues that could also impact the transmission. To mitigate these issues, it is advisable for owners to ensure proper handling of the spark plug tubes during valve cover replacement, check the transmission fluid level and condition, and consult a transmission specialist if problems persist.