There is a vehcle with the nomenclature of M577, but it's not a tank - it's a command vehicle, and a variant of the M113 armoured personnel carrier.
The US Army tank platoon in Vietnam held 5 Patton tanks. 3 tanks were called the heavy section, and the remaining two tanks were called the light section. After the VN war the US Army changed to something more closer to the metric system; 4 tank platoons.
the US Army invented the Sherman tank.
around 10,000
In Vietnam the US Army's M48A3 Patton tank held approximately 300 gallons of diesel fuel.
The US built Sherman medium tank.
During the Vietnam War the standard US Army M48A3 90mm gun Patton tank utilized white lettering. US Marine Corps M48s used yellow lettering. Example: the US Army tank would have "US Army then its serial number" in white letters stenciled across its sponson boxes, while the US Marine tank would have, "USMC" in yellow stenciled across its boxes. Note: The sponson boxes were constructed of sheet metal and welded/bolted to the sides of the tank on each side on the fender; they held tools, etc.
The United States Army of the Plains during the 1800s were called the US Cavalry. They were also called bluecoats or yellowlegs.
During the Vietnam era, the official US Army designation for a tanker was, "Armor Crewman."
During the Vietnam War, a US Army "Troop" was a US Cavalry "Company." Example(s): "A" Troop, "B" Troop, "C" Troop, etc. The Australian Army in Vietnam called their "Companies" a "Squadron", and called their "Platoons" a "Troop." (During the war) The US Army standard "Infantry" Platoon was approximately forty men. An "Armor" platoon (in Vietnam) consisted of 5 Patton tanks per platoon; with 20 tank crewmen per platoon...led by a 2nd or 1st Lieutenant.
cavalry
The M551 Sheridan aluminum tanks used in Vietnam were called she's; but the Sheridan tank itself was named after a "he." General Sheridan, US Army, War of the Rebellion (Civil War).
The Vietnam era US Army M48 Patton tank weighed about 52 tons combat loaded. The Army's M551 Sheridan tank in Vietnam weighed about 17 tons. The Australian Centurion tank in Vietnam was about 50 tons.