In post
https://mustangforums.com/fb.asp?m=433470
I read about a TSB on a fix for a binding sensation in the rear end while turning corners, I have this.
It says they will replace the clutch pack and add a different additive... yadda yadda'
For performance reasons I'm not sure that I want a lighter spring limited slip, Is this the
Fix? wouldn't I be better off keeping my tighter clutch pack and having the fluid changed to synthetic
with the additive, see if that fixes it, and only if it is still a problem have them perform the TSB?

 

Just about every limited slip diff I have ever seen does this to some extent. This is not an issue common to Ford and certainly is not anything more than a minor annoyance. I had two old Chevy pickups that both did this. Basically what happens is when you have been driving straight for a while and not driving around corners the diff tends to "lock". When you turn a corner and the inside wheel needs to turn slower you will hear and feel the clutch packs releasing and grabbing again. There's nothing at all wrong with your diff. The additive will help. In my case it helped alot. It didn't completely eliminate the problem but it helped enough that it didn't bother me anymore.
I'd just put in the additive and live with it. Sure using lighter springs will help but it will also reduce the effectiveness of the unit. If you want a totally smooth operating vehicle don't drive a muscle car. > insert cheesy grin here <