Typically, if tires on the M35A3 are found to be flat, you might have LEAKS in the very system intended to maitain/adjust the tire pressure. (CTIS= Centeral Tire Inflation System)
Such leakage can be very minor and simply allow a slow release of air pressure that the compressor can overcome.
HOWEVER, such leakage can also be indicative of a MAJOR MALFUNCTION in the system that could be impossible for the system to "self-fix".
This is why MANY M35A3's have the CTIS disabled, both by the Military AND by MANY Volunteer Fire Departments that acquired these trucks for that "wonderful" feature - handy on BrushFire Fire Trucks that run over cactus, thorns, sharp rocks, and debris. Many civilian owners have also given up on maintaining the CTIS and have simply disabled it.
Be sure to do you homework before attempting a drive-home recovery, and be prepared to have it hauled home.