hi. i have a 51 reg td4. i took it for 2 new tyres today. after they were fitted, i drove down the road. when i got to about 30 mph there was a real loud grinding from the front of the car and very bad knocking and vibration. The garage are saying that its just coincidence, and the front dif and propshaft are knackered. is there anything that they may have done to cause this.