Low drone noise in 2010 sv6 wagon

[Daggwood]

Hello All First time I actually need to start a new thread on this site and only because the dealer is stressing out my BS detector.
Anyway problem is as follows On my stock 2010 sv6 wagon at 1100-1600 revs in 5th an 6th gear, I have a grumbling or drone though the car give it a little bit more gear changes down goes away. It's also noticable at low revs and I have backlash in rear quite often although not at same time. A low vibration is felt through steering and seating when this is occurring.
i have been told it isn't the engine or trans mounts, prop shaft or donut issue etc as I have the upgraded versions on the car from factory and that this noise is all within tolerance and they all do that.From the other cars I've driven I have not heard it.(same models similar klms we have 3 in the family)
Gone down the line of wheels all have been balanced and aligned and road force tested all within manufacturers specs.
My gut feeling is that it's still to do with the drive line somewhere but I'm not a mechanic the cars only done just over 30000 klms so this seems odd.So short of getting another opinion I'm looking for some feedback if anyone else has has this problem and did it get fixed? Cheers

[brgsv6]

I'd take it to Holden.. It is under warranty and (you'd think) they know best

[astroham]

i have a 2010 sv6 ... make them check the tail shaft apparently the ones in the manual have a bad habbit of failing ... (around 40% is the figure i was given) ... dont know about the autos though

[nazphu]

i have a 2010 sv6 ... make them check the tail shaft apparently the ones in the manual have a bad habbit of failing ... (around 40% is the figure i was given) ... dont know about the autos though

Wow, didnt know that was such a common problem for others... My 2007 SV6 tailshaft couplings have failed 3 times...

[Daggwood]

Well you would think that in a 2010 model this issue would be fixed HMMM.
I was also talking to a local trans specialist about it seems to think that the trans fluid in the 6 speed auto goes bad quickly and stops it changing properly giving a grind noise between 5/6. (again the BS detector went off)