I have the 2011automatic v6 mustang and when I put my car into reverse or drive it makes a noise. I was told by a mechanic that it was a u joint on the back end of the driver side? Only problem is is that they don't sell u joints at any car parts store lol. So is it really my u joint?

 

could be a lower control arm bushing

 

I think he means the knock,bump,clunk. Probably the driveshaft slop with the 2 piece design. Happens to most of us sometimes when going from P to D or P to R or even D to R or R to D. But for the most part I have read all over the forum that the clunk like sound appears when you come close to a complete stop.

But there is a TSB for the control arm grunt/creek noise
http://v6mustangperformance.com/repa...r-control-arm/

 

I believe all the automatic have the clunk sound. Mine does. I say it is normal but could be a bad u joint. If your local car parts store can't order you one, then you'll have to order one from your Ford dealer or a Ford dealer on line parts store. I still say its normal

 

I have a 2012 3.7 Auto and do not have a clunk.. I am going to get a one piece driveshaft anyway..peace of mind and weight reduction makes it way worth it to me.