should I be worried ?...

[trevytrev]

Took the S out on the weekend for a good 4-5 hour blast, just before I got home I noticed a strange knocking noise that seemed to be coming from the back of the car. It only appeared to happen when going up a hill with low revs and it would knock faster as the rev's built up going through each gear.

So I have jacked up the car, checked everything to do with drive for play but can't seem to find anything wrong. I took the car out last night for about an hour and everything was fine..

anyone got any ideas of what the cause could be ?

[z_chromozone]

Likely to be the UJ's if it is speed related.

Z

[greenv8s]

Yes, those are the symptoms of a damaged CV joint. In my experience they tend to fail in pairs so it is worth replacing the pair while you have it in bits. They aren't expensive or difficult to replace.

[gefopsman]

UJ,s sounds favourite. Part number listed on the Parts List is incorrect. Quinton Hazell QL16103 (only one 1) is the correct part.
Just changed mine. You need to drop the diff to get the prop out but it was not too difficult.
Don't forget to mark both yokes and the shaft to ensure it goes back the same way. Otherwise it will be out of balance and could vibrate.
Worth changing the gearbox rear mount while the pipes are off. This is off an 87 Transit.