OK, a M75 with a load of scrap metal welded in place. Basically the same chassis, and at first I thought it was a British '432', but the engine hatch is a different shape, and the top decking slope different too. Like the AFC M113, the basic '432' chassis was used in many configurations, including the '434' engineering vehicle, and 'Abbot' SPG, and is very similar to the 113 family.
It was 'Abbots' and '432's' which were modified to resemble Stugs and PzKfw IVs in 'Band of Brothers', and similar movie productions.