I think you are after a regimental history rather than just an OOB as they don't contain infomation on deployments, casualty and resupply rates. In which case you want to be checking out military history book sellers websites. 2nd Armoured "Hell on Wheels" is Patton's division so I imagine you'll be spoilt for choice. It might also be worth checking to see if the regiment has its own historian (most British regiments do, don't know about Yankees) and then getting in touch with him about the infomation you require.
With regard to OOB, online resources can be unreliable at best but if you have lots of free time you could try the excruciating detail of the Nafziger Collection, found here:
http://www.alternatewars.com/CARL/Nafgizer_CARL.htmOtherwise, this is the best I can do for you, it the TO&E for an armoured battalion:
1 x Battalion HQ Company consisting of:
1 x HQ: 2 x M4A3 Sherman, 1 x M3HT, 4 x Jeeps.
1 x Armoured Artillery platoon: 1 x M3HT, 3 x M21 mortar carriers.
1 x Recce platoon: 3 x Sections each of 2 x Jeeps + HMG
1 x Armoured Gun platoon: 2 x M3HT, 3 x M4/105mm or M8 HMC
3 x Medium Tank Companies each consisting of:
1 x HQ: 2 x M4A3 Sherman
3 x Medium Tank platoons each of: 5 x M4A3 Sherman
From the Autumn of 1944 onwards M4A3 (75mm) can be replaced with E8 (Easy

76mm.
1 x Light Tank Company consisting of:
1 x HQ: 2 x M5
3 x Light Tank platoons each of: 5 x M5
From December 1944 onwards M5 can be replaced by M24 Chaffee