I have a question about my 1985 300sd ; I spent Saturday replacing my axels and noticed on the left side when I moved the Axel it had some movement in diff with some slap.

Car has 346,500 miles.

Now when I Installed right side first that was tight and rotated smoothly. So after completing the job went for a spin and man what a difference no more clunk to clunk.

But the diff still has some, what gives? is there a nut on the front of diff behind flex disc?
If so could that need tightened up or replacement of nut then torque?

As always I appreciate your help.
greazer2b