Strange almost “goose honk” noise while dropping gears during acceleration

[Bitbythebimmer]

Hey guys,
Picked up a 2007 Z4 si and everything has been pretty awesome so far but I noticed an odd sound while punching the gas. Seems to happen when the auto trans drops 2 gears on a hard accel. Doesn’t do it in paddle mode or I haven’t been able to replicate it. It’s a very short goose honk type noise for a split second while the trans is about to drop the gears. Hard to say exactly where it’s coming from. No real lag or shuttering when engaging. Main concern is further damage obviously. Any ideas? Thanks

 

[MJJamieson]

If it had been a manual I would have said clutch slip but not sure on an auto. Maybe check the oil level to start with?

 

[NickDE]

Mine does it when I have booted it and it changes back up a gear as speed picks up. Also an auto. When overtaking the goose honk means it is time to pull back in to the left lane.