Sliding Tile Board Game--Lingo Bingo?
I've been able to find a partial match for what you're describing. It isn't your exact game, but I'm posting it hoping it'll help someone find that game &mdash; it sounds like a possible ancestor or derivative.

The former Ideal Toy Company produced Logus Sr. and Logus Jr. in 1971. This is a 2-player game that gives the players a 4&times;5 grid of letters, two spaces missing, making for 18 letter tiles. You're assigned challenges of various formats by cards. There's no wheel and there's no 4-player.

 

First: Logus Sr. Image credit: Bagherra on Board Game Geek. // Second: Logus Jr. Image credit: Amazon

(Logus found thanks to Graham Toal, Steffan O'Sullivan, and the wordgame-programmers mailing list.)