2006 3.0d auto X5 vibration through floor

[c76jon]

Hi all

Would appreciate some help please

2006 X5 3.0d auto

Full dealer history and very well maintained

I have a vibration which can be felt through drivers floor at about 2200 revs

Does not happen when you just rev engine as far as i can tell

Have to be in drive

goes when revs climb

Really really annoying as rest of car is perfect

CAnnot feel through s/wheel or gear lever

Only through floor

Drives well and pulls like atrain

Car has been 4 wheel aligned and wheels perfectly balanced

No other noises whatsoever

Car has done 100k but not abused and maintained without thought to cost

Please help it is driving me mad!!!

Many thanks

John