Click from trunk when car hot and starting from a stop
 

OK... I know there's loads of threads about clicking and noise from the trunck, in particular here's one I've found pretty comprhensive:

http://www.ft86club.com/forums/showthread.php?t=13451

However, my case seems a little different, it is a unique click in the trunk:

This happens ONLY when the car is warm (after at least 5 or 10 mins driving). When the car is fully warm (after 45 mins) it seems to reduce. When cold there's NO WAY to get the noise.

This happens EVERY time you start from a stop (just 0 to 5MPH, just when the car starts moving forwards, you get ONE click).

It happens often and repeatedly on rough roads at constant speed and straight line (many clicks). It happens often in roudabouts or when zigzagging at constant speed.

IT happens with seats up or down. The trunk is empty (jack, spanners, screw driver... all is out).

I've done a drive with my daughter in the back so she was searching and pushing/poking around at the plastucs (back tray, rear trims, ...). Next step I'll try to drive her (my daugther) with the back seat down and her in the back so she can try to spot the source... need to wait for sunday afternoon on an empty super market parking for this...


Tomorrow I'm going to to take it to a "vibration machine" (you park your car on it and it makes the wheels vibrate at different speeds and heights) to see if I can produce it at a stop on this machine (then get in the trunck myself to try to locate the sound). I've been to Toyota Dealer who have sent a report to Toyota to see what they say (no reply yet).

The car is a GT86 Manufactured in Sept 2012 (so after the June 2012 rear deck change).

That's it.... any ideas?