545i 3rd gear grind.
 

I've noticed that when I am cruising in third gear and keep my hand resting on the shifter I can feel the shifter vibrating noticeably versus any other gear. Also when I am shifting from 2nd to 3rd at high RPM's it makes a grinding noise before engaging. This happens even after the car is warmed up it also happens if I'm down shifting at high RPM's. and when i mean high RPM's its roughly about above 4k. It never grinds when i shift lower than 3k RPM's.

Anyone else have this problem? Could it be the synchros?

Sorry this is wild guess with BMW but I had same situation In my truck and my synchros had gone in the trans.

Agree it could be the synchros. But I remember reading somehwhere it is not a good idea to leave your hand resting on the shifter. Can't remember why though.:think:

are synchros hard to change on a 04 545i? anyway i can test them out or something other than taking it to the dealership?

Do you slam it into gear alot, or race into gear? Slamming gears while hauling ass?

Maybe this guy is in your transmission:

http://img1.wikia.nocookie.net/__cb2...-my-gears1.jpg

no I never slam it into gear or race into gear. when Im going fast i pay extra attention to how i change gears. I treat this car carefully to avoid any damage from negligence. it just randomly started doing it