Groaning,vibrating noise :-(

Hello all

I have just bought a 1998 Freelander XEDI
It has a annoying problem which I hope I can fix cheaply

If I go through the gears leisurely there is this awfull groaning and vibrating from underneath but...if I go through them giving it some stick its virtually gone.

This is making my fuel consumption a bit poor because im always giving it some

Im sure you have had this query many a time, I just cant find any

Thanks in advance, Darren