This is a mystery halftrack.
Years ago I purchased a collection of used Roco and this was one of them. The guy was using it as part of his Afrika Korps. One look at that US Army truck cab and M41 type tracks and running gear told me that was not going to happen in MY army.
This is one of those strange little vehicles that you sometimes get when you buy a used collection. It is a conglomeration of at least two different vehicles. I don't know who make the tank tracks, they are not Roco.
This reminds me of the sort of vehicle the rear echelon types put together after some major combat when they have plenty of parts, lots of time and not much to do with either. So they make something out of the junk.