Click-Clack preferred to sleep in a corner, or better yet a hiding place, but sometimes he tried sleeping on one of the Dinotrux.
Dozer had a good combination of traits as a Trux to try napping on. First, Dozer was always grouchily determined to find the best spot and be comfortable. That meant he didn't move around once he had selected somewhere. But Dozer was also a light sleeper, so he would wake up at any disturbance or danger. Probably he would, anyway. Click-Clack could be fairly sure. Maybe he should try to keep one of his own eyes open for trouble, just in case.