The End of the World (apocalypse)
1985 300zx 2 seater why is there a knocking sound from the rear end when you accelerate doesn't do it any other time?
Rear U-joint causes knock. happens to almost every 300zx. mostly noticed in automatics.
I have owned all z31 zx's 84-89 except 88.
it will not damage anything, you can put 200k miles with this knock. Just annoying.