I feel a bit of a fraud because i read lots of issues on here and have no clue ,my current problem is i have a knocking coming from the diff every time i take it to the garage it stops

12 times and the men in the garage say they need to hear the noise to tell which diff is causing the knocking. Its intermittent and can be very Loud any ideas would be greatly apricated.  

Morning

Diffs normally whine and moan which gets louder with speed, knocking is unusual as if something in a diff is broken it will normally go with a bang. Drive shafts can cause knocking if the CV joints are failing. However, a garage would see that or should 

The Transfer case and front prop shaft are other abused components.

So basic stuff first Tyres, does your car have a staggered set up (wider rear tyres) ? Check the sizes carefully, are they correct for your car ? Are they all the same make correct sizes and are they wearing at the same rate. Any incorrect tyres will cause transmission wind up which could be the cause of your problem

If your car has a staggered set up tyre sizes would normally be 235x50x18 Front 255x45x18 Rear or 235x45x19 Front and 255x40x19 Rear Check them carefully and make sure they are all the same brand, or it could cause expensive damage far mor expensive than a set of correct tyres

Dave

Sorry Grey Dog I gave the Garage All the info and they said it's the drive shaft. And should have Done it last Wednesday but still waiting

Thanks for the advice