I didnt think the td4 was prone to hgf?.......have you checked the brakes are not sticking on yet?
+1 .....feels like towing a trailer even without one on.....rear brakes got to be suspect, do a search o the topic and you'll see they aint the most reliable things in the world. You may have a lining parted company from a shoe or sumthi daft like that. Dont need a good garage for that, pop into tyre shop and they will check for free.