Front end knock
 

Hi all i have a 98 uk2000 . When i drive the car i get a knockin from the front left it only happens when i go over speed bumps or dodgy parts of road if im going slow ? I have just been under the car & the drive shafts have a lot of play at gearbox end. Could this be causing the knocking. Is there suppost to be any play atall ? Thanx