reverse gear clunk

i have noticed the last couple of days that when i put my 71 super into reverse and back it up that the drive engages with a loudish and very sudden clunk at which point it starts to move......i know this cant be good (im no where near a mechanic) woudl this be gearbox? or what.........please someone in the know tell me........im hoping to do up the car on the cheap and get it going and looking good for rego but i have a feeling that im gonna have to spend more than i want.......it didnt make this sound when i got it

try and adjust the clutch the way you worded it is as though your clutch needs adjustnent. My beetle did the same thing and only in reverse not any other gear adjusted the clutch and now is fine try that and see how you go. Graham

awesome that sounds alot cheaper than what i was thinking :thumb thanks for your help