Oddly, I was in the army at that time and left with a rank of Specialist 6, pay rate E-6. Specialist 6 is a rank that no longer exists, ranks of specialist above 4 are now given the equivalent sergeant rank.

Army enlisted ranks were:

E-1 PVR, Private Recruit, no insignia,
E-2 PVT, Private, one chevron
E-3 PFC, Private First Class, chevron and rocker.
E-4 SP4, Specialist 4, eagle badge (now just SPC)
E-4 CPL, Corporal, two chevrons
E-5 SP5, Specialist 5, eagle badge with roof
E-5 SGT, Sergeant, 3 chevrons
E-6 SP6, Specialist 6, eagle badge with two roofs
E-6 SSG, Staff Sergeant, three chevrons with rocker
E-7 SP7, Specialist 7, eagle badge with three roofs
E-7 PSG, Platoon Sergeant, three chevrons with two rockers
E-8 MSG, Master Sergeant, three chevrons with three rockers
E-8 FSG, First Sergeant, three chevrons with three rockers and a diamond in the middle
E-9 SMJ, Sergeant Major, three chevrons with three rockers and a star in the middle
E-9 CSM, Command Sergeant Major, three chevrons with three rockers and a wreathed star in the middle
E-9 CSA, Command Sergeant Major of the Army, three chevrons with three rockers and an eagle in the middle

W-1 WO1, Warrant Officer, Gold bar with color mark
W-2 WO2, Senior Warrant Officer, Gold bar with two color marks
W-3 CW3, Chief Warrant Officer, silver bar with color mark
W-4 CW4, Senior Chief Warrant Officer, silver bar with two color marks (There is now a W-5)

C-1 to C-4, Cadets at military colleges

O-1 2LT, Second Lieutenant, one gold bar
O-2 1LT, First Lieutenant, one silver bar
O-3 CPT, Captain, two silver bar
O-4 MAJ, Major, gold oak leaf
O-5 LTC, Lieutenant Colonel, silver leaf
O-6 COL, Colonel, silver eagle
O-7 BRG, Brigadier or Brigadier General, one star
O-8 MJG, Major General, two stars
O-9 LTG, Lieutenant General, three stars
O-10 GEN, General, four stars
O-11 GOA, General of the Army, five stars

Warrant ranks were the same in all services, officer ranks up to O-10 were the same in Army, Air Force and Marines. The Marines had no five star general, and in the Air Force, that rank was called General of the Air Force and abbreviated GAF.

Enlisted ranks in Air Force and Marines were similar to Army but different in detail. An E34 in the Marines was called a Lance Corporal and the rank below that was PFC with the lowest rank just called private. Privates in the Air Force were called airmen and the Air Force had no Corporals or Specialists, starting the rank of Sergeant at E-4.

The names of the sergeant ranks were different in detail. E-7 in the Marines, for instance was called Gunnery Sergeant, nicknamed Gunny, a name sometimes applied to Army sergeants in the Artillery. Sarge was the nickname for almost all sergeants except First Sergeants were called Top.

Specialists were nicknamed Spec, Specs, or Birdie except that airmen called Army specialists Sarge.

Navy enlisted ranks involved Seamen (~Privates), Petty Officers (~corporals and buck sergeants), Chief Petty Officers (senior sergeants), and Ratings (~specialists). The insignia was pretty simple being hash marks for seamen and chevrons and rockers for PO and CPO ranks. Ratings had a badge showing what their rating was in, like a medical symbol for a corpsman (medic) or a lightning bolt for a radioman or a gear for an mechanic.

Navy officer ranks were Ensign, Lietenant Junior Grade, Lietenant, Lieutenant Commander, Commander, Captain [Lower Half], Captain [Upper Half] (aka Commodore), Rear Admiral, Lieutenant Admiral, Admiral, Admiral of the Navy. The shoulder insignia for officers in the Navy was the same as for the equivalent pay rate in the army. Note that a senior Captain wore a star, like a Brigadier General, while a junior Captain wore an eagle like a Colonel. Commodore was less a rank and more of a job title, a captain commanding a fleet.

Navy ranks could also be shown by sleeve markings on dress uniforms, the other services had no equivalent except that in certain assignments, Marine officers might be wearing a Navy-type uniform or vice versa.

The Coast Guard had the same ranks and insignia as the Navy, except no five stars, as did the Uniformed Medical Service which was a non-military uniformed service serving in disaster areas around the world. The Surgeon General was a full admiral in the UMS.

Is that enough? :)

Hugs,
Erin

= Give everyone the benefit of the doubt because certainty is a fragile thing that can be shattered by one overlooked fact.