Heard a noise last night

[bs175dths]

side-to-side play or any play for that matter, in the rear wheel
cracked or broken shock support on the final drive unit
loose or stripped lower shock bolt on final drive unit.

Take the saddle bags off, put the transmission in gear (engine off of course - (hey! some are out there)), dedicate 30 minutes or so and poke, prod, wiggle, jiggle, push and shove parts at the back of the bike until you are convinced all is tight and good and as it should be.

My 84I came to be with a broken and repaired shock support on the final drive. It broke again because the original repair did not weld across the break.
I had it welded.
I did the cleanup of excess weld to allow the bolt to go through and the shock body to fit properly.
That was 20 - 25,000 miles ago.

Good Luck and keep us posted.

-Ride On