I've never heard of Wilson Transmission, which doesn't necessarily mean anything... Could the tag be from a company that serviced or installed the transmission, instead of the manufacturer?
Post some pictures; someone may recognize it.
Hard to say what it does for the truck without being sure what it is...
If it is in fact a 3-speed auxiliary transmission, which is what I expect, it means you can start out a heavier load and that the truck will run down the highway faster than the brakes make smart.
