[killahurtz]

I have a 2006 BMW 325i E90 with ZF automatic transmission. The transmission makes a brief screech sound when shifting up from 3rd to 4th and when stepping on the gas to pass another vehicle. What can it be?

I found a video on YouTube that replicates the same sound my car makes. Check the link please.

[lowrydr310]

I had a similar issue, then I read a post about someone else with the same problem who found a solution from a Jaguar which also uses the same ZF 6HP transmission.

I did a simple drain and fill of the transmission fluid and it solved the problem. When was the last time your fluid was changed?

[killahurtz]

I had the transmission fluid changed about a year ago.