Transmission growl on my Golf X2
 

I have owned my X2 Golf since 2011. I have 3400 Km on the X2. The drive cushions were replaced last year even though the originals were OK. I now hear a gear growling noise that has just started. The X2 performs fine. It sounds like a pair of gears have lost their running clearance and are bottoming out. The noise seems to occur strongest when just starting to ride and gets a bit quieter after about an hour. I am looking for best guesses for the cause.
Thanks in advance,
Steve