Okay. I finally made time to open up the front of the rear diff. I pulled off, in this order, the pinion nut, washer, u-joint connection, seal, and pinion bearing. The bearing looks to be in good condition.
With the bearing pushed as far up the pinion shaft as it will go, I can still move the pinion into the housing by a 1/4 to 1/2 inch.
Any ideas what might be missing? What's my next step? Do I need to remove the axles and pull the whole 3rd member out? I can post pictures if that will help with troubleshooting. Thanks for the help.