Sherman 105mm Howitzer or Not?

The unit organization of 186 Sherman tanks in an Armored Division is subject to many variables.

One of them is the availability of the M4 Sherman with 105mm howitzer.

In North Africa they used the T19 105mm howitzer mounted on the M3 Halftrack instead.

Some of these units went on into Italy and later Southern France with the T19 halftrack rather than the Sherman 105mm howitzer.

Others used the Priest 105mm howitzer and I think some of these landed at Normandy or soon afterwards.

 So while you got 186 Shermans some might actually be M7 Priest, or T19 halftracks.  And of course in North Africa the US started with Lee tanks which saw only limited combat before replacement.  Also in North Africa the Armored Division had a different organization above company level, so much was different there.

Tank Division Tank Organization

186 Sherman tanks in a US Army Armored Division as of September 14, 1943.  So by Normandy on June 6, 1944 most units were to this standard.

That's 5 tanks per platoon x 3 platoons + 2 platoon HQ + 1 105mm assault gun M4 = 18 tanks per company.

3 companies per battalion = 54 tanks + 2 HQ tanks + 3 105mm assault gum M4 = 59 tanks per battalion.

3 battalions per division = 177 tanks in the tank battalions +

3 HQ batteries of the Field Artillery Battalion with 3 M4 each = 9 M4 tanks + 177 in the tank battalions = 186 M4 Sherman tanks total.

That's the standard.  Most US Army tank battalions were at full strength when first committed to combat, and damaged tanks tended to be replaced or repaired fairly quickly.  When a unit suffered catastrophic losses it would often be pulled out of the line to be re-established.