I've transited in PVG before, although it was MU-MU connection on a HKG-PVG-YVR ticket.

At PVG, you need to clear customs upon arrival (wait a bit for the supervisor to waive you through without a visa because your transit), get landside, and go back upstairs and clear customs again. The whole process took me more than 1 hour!

I suggest you ask the first carrier to check your bag to PVG only and go claim it yourself and recheck.