In Flames of War, guns that are limbered to a truck to move are just dragged behind. In some cases it doesn't seem too odd, but I still find it a little strange to have a fully deployed gun with its crew, somehow surfing behind a truck or halftrack.
Where this is especially strange is the 8.8 Flak 36. It is a huge gun on a cruciform mount, and until it's attached to its wheel limber, wouldn't move short of a tank hitting it. I did not want to have such a look, and the Flames of War model thoughtfully comes with limber halves. I set about converting the rest to have limbered versions of my unlimbered guns, for when they're dragged behind their halftracks:
The base of the gun went next, and involved a bit of guesswork. The detail is simplified from the real gun, as I hope in most games to not ever have to use their limbered versions! Again, the BF gun shield made a great trace proxy for the custom version.