After 100,000+ miles of normal operation the 2002, BMW X5 4.4 began exhibiting unusual transmission operation. At random times, during start up, the transmission shifted to neutral, allowing the engine to rev very high, then engage in 1st, causing an abrupt lurch forward. Also, it will experience this disengagement sometimes when down shifting into passing gear, causing the engine to rev, and a loss of forward motion, and then an abrupt engagement, resulting in a major lurch forward. This was a major safety issue, as you cannot be certain the transmission will engage or disengage when pulling into traffic or performing passing maneuvers. After researching this problem there is considerable information about this on the internet as it is a common problem, and has been identified now for more than 3 years. It is related to zf supplied transmissions on BMW and Jaguar vehicles, and is attributed to the controlling software the BMW dealer suggested I replace the transmission at a cost of $7,600, and has not indicated a willingness to explore software solutions or admit any common problem existed. Reports on the internet indicated that sometimes a software update will cure this problem, and sometimes not, as it occurred in both old and new vehicles. As an expert in this field, I am still conducting my own analysis, but am coming to the conclusion that this is a BMW and zf problem that needs further investigation by NHTSA as a critical safety hazard in the affected vehicles.

- Aptos, CA, USA