I've been racking my brain and searching Google for images, but I can't for the life of me remember. Most of the pictures I see DON'T appear to have a visible fuel tank, but obviously some do. Forty or so years ago when I worked for Boise Cascade Corporation, we would order a refrigerated semi full of tree seedlings early each spring. I lived in the pine trees and my driveway was shaded by trees, so they always parked it in my driveway, which meant I had to maintain the thing for the several weeks it sat there, running 24x7. Each morning we would pull boxes of trees for planting in areas where the snow had just melted and we could hopefully get in on the roads. I had to check temperatures in the van and fuel levels morning and evening, and refill the diesel if it got low. I'm sure it must have had a tank somewhere, as I don't think they build them into the units, but my memory is failing me badly. You would think I would never forget that! It think it was probably as KAMM says, but my brain just can't remember.
There are lots of things about this thread that don't make sense to me. First the OP has been a user since 2012 and this is the first time to post? Second, the thread is created in a mostly dead forum. And lastly, it is a complaint about Dave's truck trailers? Of all of Dave's creations, these trailers prompted a some what confrontational first post not directly addressed to Dave but a solicitation for "Someone" to take action? Strange.