Can the am/fm antenna on a 2011 gmc sierra 1500 be taken off with a wrench, or is there more to it?

Called the dealer where I purchased, he could not say for sure.

 

Yep, if you're just removing the antenna mast, the flexible part, then yes, there is just a hex at the bottom of the antenna that you can turn to remove it.

Upon installation of your new antenna, I would put a very small dab of blue loctite on the threads just to make sure it doesn't go anywhere. Almost all of the older used vehicle I've had in my time have had loose antenna masts that cause a bad radio signal.

 

Thanks.

 

Should be able to no-problem.

I agree with the loctite bit as well- My mother always replaces her stock antennas on her F-350's because they smack the house when she backs into the garage. She had 3 aftermarket ones stolen right off the truck before she started gluing them!