As a possible temporary fix until you get your new TV here's something that might work. As contradictory as it sounds sometimes the "fill" or "full" options on certain TVs crop a bit from the edges. Not only from the sides but a bit from the top and bottom as well. If your connection is through an HDMI cable this could be the case. If available you can try setting your picture size options to "standard" or whatsoever your TV's other options are. Sometimes that setting will display whatever the original aspect ratio of your chosen media. Only downside is if something is letterbox it'll show as 4:3 with the respective empty space that you have to zoom in anyway. Alternatively if your using a blu-ray player it could just present the letterboxed DVD image stretched out instead of 4:3 ditto for native 4:3 DVD content.

Another thing is that what Bingowings alluded to is entirely correct for some TVs. Sometimes depending on the connection while you get the "same" options for each input it's merely the label that is the same. Meanwhile what you actually have are separate options entirely. Complete with separate zooming capabilities. Though I think it's more a software issue than an internal hardware preference.

...Then again I'm no HDTV expert so whatever....

TL;DR try playing w/your picture size options.