Front - Take the Doors off. They Should have a couple screws in the door, and than it should pop out. You can either go buy the door popper tool(10.00 BUcks at Checker), or just pop them with a screw driver. Depending on how old they are and how many times they have been poppe, they will more than likely just break. SO Be prepared to get new ones. Rear - Take the whole paneling off. It's really not that hard.
The stock size of the speakers in a GMC Sierra are 4x6 in the rear. If they have not yet been switched out with an aftermarket, they will be the 4x6.
autozone.com has online manuals that give step by step how to
remove the belt and usually it will be a 13mm nut to remove from the front of the compressor and everything should pull off fairly easy
If your talking about the door speakers then you will have to remove the door panels to get to the speakers.
6x8 Door Speakers (Front & Rear)
6.5 for the front
near the front differential
the front door and back door speakers are 6" x 8 " speakers
6X8 inch speakers for front and rear doors.
6.5 Matthew D.
In the 1997 - 2001 Cherokee the front door speakers are 6.5 inch. However they do not match 6.5 inch aftermarket speakers.
The 1998 BMW 323 front speakers measure three inches by five inches. The rear speakers measure six inches by eight inches.