I'll check again. It's a two size spacer. One end is larger than other with a bend out in the middle instead of taper. Supposed to crush as you're tightening and measuring tongue. I'll get in the FSM parts manual and look. It's a sure-grip 2.76 diff
On my 69 I'm trying to find the crush sleeve, pinion spacer, preload spacer, whatever it's called but I can only find complete rear rebuild kits. Anyone have a source?