Thanks to portrayal press I now have the following Technical Bulletin copies that certainly shed a lot of light on the Halftracks and Quads winterization kits!
TB 9-2855-25
Installation instruction for M45F power plant heater kit for M16A1 Halftrack.
TB 9-2855-27
Soft top closure kit M16A1
TB 9-2855-28
Halftrack power plant heater kit for M16A1, M16, M15A1, M3 and M3A1.