2005 mustang

#1

2005 mustang v-6 65,000 miles, auto makes rear-end clunk when put into reverse and also going into park. u-joints?

#2

Other possibilities too. With the car up on a hoist look for the slack visually. Might be in the rear axle, like ring and pinion or axle shafts @ spider gears , slip yoke @ transmission, or even inside the trans.