Hello, mendo
The M105 is to tall, too heavy and too wide. It will all but guarantee damage to the truck in tight turns or when crossing a ditch or starting up a steep driveway from a road. Add to that the 2,700 pound empty weight with no brakes and you can expect jackknifes on level dry roads, let alone in reduced traction driving.
I served in two different leg infantry battalions that used M561s as mortar carriers and we hauled M101 trailers for additional ammo. If the tops are on the goat's carrier and on the trailer they can get into contact when starting up or coming down and abrupt transition such as a steep roadside bank. It gets worse when you go up while turning since the corner of the trailer is closer to the carrier. Use some caution and anticipate the clearance issues and you'll be fine.
Lance