Complex sentence: Many M1028s were upgraded at the company level to M1028A2 and A3 specs--the dual wheel rear end arrangement was a result of the M10128 flipping on its side because of the high center of gravity when carrying the equipment shelters.
Split into simpler sentences: Many M1028s were upgraded at the company level to M1028A2 and A3 specs. The Dual wheel rear end was a result of incidents where the M10128 flipped on its side because of the high center of gravity when carrying the equipment shelters.