A slide out room assembly for installation into a motor vehicle includes a slide out room (20) having first and second opposed sidewalls (26) and a frame (34) configured to slidably receive the slide out room (20). An upper and a lower gear rack (46, 48) are disposed on each of the first and second sidewalls. First and second drive mechanisms including upper and lower pinions (52, 54) are attached to first and second jambs (40, 42) of the slide out room. The upper and lower pinions engage with the respective upper and lower gear racks. The frame may be installed in a motor vehicle adjacent a door (18) of the vehicle such that the assembly is fully contained within an interior of the vehicle and the door may be closed when the slide out room is in a retracted position. The slide out room may be extended through the door of the vehicle when the door is open. The assembly may be installed into and removed from a vehicle having relevant government crash and/or emissions certification without voiding the certification.