Clunk when shift to reverse

[Brem95]

Hope everyone is doing well, I have a quick question in regards to my current issue on my 5 speed Manual 97 sport. Sometimes when I’m in reverse I hear a single clunk from rear end once I actually start reversing. What should I be looking at first? U joints, rear diff?

Thanks and have a great day!

 

[freak]

Set the brake, chock the wheels, make damn sure it can't move. Motor off, put it in neutral, crawl under and start twisting the driveshaft to look to see whats loose.