[Bryan_C]

Here is what I found: Remove the upper glass run felt, remove the screws for the tailgate seal, then you can remove the sheet metal screws holding the three pieces in place. Keith was correct - remove the side pieces first then the top. There is a rubber seal between the fiberglass parts and the body.

Note: The 1973-74 Suburbans use a separate upper glass felt run and a separate lower tailgate rubber seal. The 1975+ Suburbans use a one-piece felt run/tailgate seal.