Knocking sound in reverse and taking off.

I seem to be getting a intermittent knocking sound and judder when reversing and taking off from junctions etc, this dose'nt happen all the time seems to happen more when the car has been driven for 30miles or so, most of the time its fine but occasionally when it does it its like being on a rocking horse, i'm pretty new to my car but was thinking maybe the final drive unit?, what do you guys reckon and how do i fix it??

could be your prop coupling paul, only reason i say that mate is i had a similar problem but worse!!. theres a bush on your prop (my mechanic called it a doughnut bush!). if thats going mate the prop starts to judder and you feel it, especially on take off or in reverse.

not defo your problem but if you can get underneath and check for wear on that bush at least you can eliminate it!

hope this helps, good luck!

Clutch seems fine in every other gear, no slipping etc, dose'nt happen all the time which is the mysterious bit.

cheers guys, i went out in it tonight and could'nt get it to do it once, its booked in at the garage in the morning, i bet the thing will be perfect when i try and demonstrate the problem.