Some Medium duty step vans (think bread trucks) use E-Torx bolts (E-10) on the rear drive shaft yoke. In the towing business I always carried my own "drive shaft bag" regardless if the company truck had a full stock of tools. My bag always had two E-10 Torx wrenches, one Snap-On and one VIM Tools, along with a full set of Lisle E-Torx sockets. If you weren't careful, you could easily round off the head of those little buggers if your socket wasn't dead-on square with the bolt head. (drive shaft in the way) So I usually broke them loose with a wrench first, then zipped 'em out with my cordless impact.
On another note..... I just replaced a rear wheel cylinder on a 2006 K1500 Chevy Silverado the other day and it was held in with two E-Torx bolts. Weird. I had no idea those could be found anywhere on a GM light duty truck.
