The LVT-3 was a new design.
In front of the cargo area was located a cab for the driver and co-driver. The gunner had a step right behind them.
The driver had a wooden box in the cab that contained wooden plugs and other materials to plug holes that were caused by enemy gun fire.
There were two Cadillac engines that were each located in a sponson on the sides. The transmissions, bilge pumps, and blowers were also placed in the sponsons.
By having the engines in the sponsons this allowed for more cargo area.
There was a ramp located at the rear and it was hand operated. The ramp had a rubber seal around it to keep the water from entering.
There was a grating that made up the deck that allowed any water that entered to drain and then the bilge pumps would remove it.
Additional armor could be added to the LVT-3's crew area.
The tracks were rubber bushed and made narrower.