I've seen some posts on how to replace the mast if it no longer goes up or down, and you hear the motor for a few seconds. This is what I just started experiencing. I purchased a replacement antenna online for less than $20.

I have a 96 ES 300.

I removed the old antenna mast and the nut that secures it, but I cannot remove the nut from the old antenna mast. The nut includes about a 2" sleeve that fits over the bottom, thickest part of the mast, but cannot slide past the grounding end cap, and if I slide up to the top, won't fit over the rounded head of the mast. I also couldn't figure out how to remove the grounding end cap so the nut could slide out.

How can I remove the nut from the old mast, and then slide it over the new mast which has the same dimensions?