I have a rear drag bass pro shop stampede spinning reel that I have no manual for. Anyone know how to disassemble this thing?

Number one, 

 

Contact BPS at Outdoor World and request a schematic. Never open any reel without one. Second, rear drags are a pain to work on even for the experienced folks. Depending on the design, you may not be able to get it completely torn down without a specialized tool. What makes you want to open it up?

Thanks for the tip. Just opening it to do some regular cleaning and lube.

If you're not experienced with the inner workings of a spinning reels I suggest you limit service to the following:

 

Remove the spool and oil the mainshaft and crank it a few times. remove the handle and cap from the opposite side. Put a few drops of heavy oil (gear lube) on each bearing. Light oil on bail arms and line roller. If you suspect the gears are dry have it serviced.