Rear end noise with acceleration only
 

When I let the clutch out, I am getting a "tock-tock-tock" sound out of the rear of my 2000 AP1. There is no noise with the clutch in, either on a straight or around a corner. Increases with speed, not engine rev.
Any ideas on how to diagnose between U-joints, rear diff, or something I am not thinking of?

Thanks!

Have you tried swapping cv cups from left/right?

Thanks for the suggestion! I watched a video on this and it makes sense that this could be the issue. The video described a vibration on take off, but I have a constant "tock-tock-tock" whenever I am on the gas with the clutch engaged. Does this still fit with CV cups? I hope so, as it looks like I could probably manage the job. What I fear most is having to replace the diff. Hopefully the CV cup swap solves the issue. Thank you for taking the time to help, clio!

With the car in 1st gear idling moving at ~3mph does it make the noise when you get on and off the gas pedal?