5K Clunk in Reverse

[Steve Sherman]

My 87 has an odd clunk that happens when I am moving in reverse.  Just
one clunk ususally after moving back a foot or so.

I've looked underneath, and did not find any loose suspension parts, and
the front axle assembly seems tight on the subframe.  So I thought I
would run this by the group to see if this sounds familiar to anyone.
Engine or tranny mounts come to mind, but I am not sure I can check
those without a lift.

TIA