Love this guy, but his hands are incomplete IMO. He needs thumbs. Warning: partsfoming ahead! Here's what it will look like when I'm done, pretty simple: I'm using the leveling legs from his alt mode, the ones that end up on his torso. I'm making a socket for the mounting ball out of black Sugru, a moldable putty-like glue. The idea is that, once the Sugru dries into a rubbery material, the leveling leg will pop in and out of the new socket, and have some room to move. I'll follow up with some results soon.
So here is truck mode with the new thumbs still installed on the hands. It's not strictly necessary to remove them. The Sugru sockets are a little loose, I may redo them. The thumbs can't store vertically in truck mode because of the prongs on the sides of the feet. I'm probably going to leave the thumbs like this, it works for me.