Ive just bought an A4 1.8T Quattro and when excelerating hard in first and second I somtimes fell a few little knocks coming through the car. It doesnt happen all the time but Im finding it quite worrying. Ive spoke to my mechanic who hasnt had a chance to look at it but said it could be a number of things. Hes not too familiar with this car and said the 4wd might not be allways on and the knock may be the 4wd engaging. Can anyone tell me if the 4wd is allways on or does it cick in at a certain speed like some other 4wds? Does this sound like something that should be happeing with this car or is something amiss? Thanks for the help. Pete.