If you hear clunks from the rear end. Chances are that the half shaft bolts that connect it to the hub flange and to the differential flange are loose.
The best way to check is to:
- loosen both rear wheel lug nuts
- jack the car up at the differential
- remove wheels
- put car in neutral and release parking brake
- make you self comfortable ... a concrete block parked in front of hub is a nice stool!
- get two 14mm box/open end wrenches and check each nut/bolt
- rotating the half shaft helps access all of the nuts and bolts... sometimes it is tricky to get the wrench on a nut or bolt.. the special technique is to simply rotate the half shaft, jam the wrench in place then re-rotate the half shaft so that the nut/bolt you are working on can be turned.
- for the deeper nut and bolt at the differential flange, a ratchet with an extension works great. (note, the bolts on the flange are compressed into the flange and do not come off)
- torque for a 77 280z with R200 is 36 to 4 ft-lbs for both ends of half shaft. With R180, the differential flange torque is 17 to 23 ft-lbs