What is that plastic "thang"?

[TomEichenberger]

OK, I dropped the pan on my 1990 Burb (6.2 w/ pre-serpentine belt config.) to change out the rear main seal, and as I took off the oil pump, a "Bake-lite" plastic "cap" fell off in pieces. It appears that this cap fit around the oil pump where the pump rod fit into the pump. By then, it was late Saturday & I had to get the beast back on the road. So...sans "cap" I put it back together. In the cosmic scheme of things, what does this mean?

[gmctd]

That was a "captive" collar, intended to retain the hex drive rod when the vacuum pump\driven gear was being removed from the engine.

Won't cause any problem until the next time the vacuum pump is removed, when the drive rod is likely to come out with it.

Just a simple matter of taping the drive rod into a 8mm hex socket\long extension and reinserting it.