I could be wrong but I believe VT-4 was active on Dec. 7, 1941 on the USS Ranger in the Atlantic. I am not that on top of Naval Aviation so I could very well be wrong and if I am please correct me. I did a search also and found this for December 7, 1941:
USS RANGER (CV-4)
The Ranger was the first U.S. Navy ship to be designed and built from the keel up as an aircraft carrier. Her keel was laid at the Newport News Shipbuilding and Dry Dock Co, Newport News, Virginia on 26 Sep 31. She was launched on 25 Feb 33 and commissioned on 4 Jun 34.
USS Ranger was returning to Norfolk, Virginia from an ocean patrol extending to Port-of-Spain, Trinidad, British West Indies when the Japanese attacked Pearl Harbor. At that time, the Ranger Air Group consisted of:
Fighting Squadron Five (VF-5) with 18 Grumman F4F-3 and 1 F4F-3A Wildcats
Fighting Squadron Forty One (VF-41) with 17 Grumman F4F-3 Wildcats and 2 North American SNJ-3s
Scouting Squadron Forty One (VS-41) with 8 Vought SB2U-1 and 2 SB2U-2 Vindicators
Scouting Squadron Forty Two (VS-42) with 9 Vought SB2U-1 and 6 SB2U-2 Vindicators
Torpedo Squadron Four (VT-4) with 3 Douglas TBD-1 Devastators
Speed was sacrificed for other essentials under the Washington Naval Treaty reducing the efficiency of the Ranger as a fleet carrier. She spent the war in the Atlantic until 1944 and then was used as a training carrier. She was decommissioned 18 Oct 46. Her name was struck from the Naval Register on 29 Oct 46 and she was sold for scrap 28 Jan 47.
Could be wrong, but I believe the TBDs aboard Ranger on 7 Dec 41 actually belonged to VS-41 and were there as a feasibility for the later establishment of VT-4.
My good source on this is unavailable right now. Hope to be able to get to it by Sunday and will see what there is then.
The three TBDs aboard on 7 Dec 41 really did not belong to VT-4, they really did belong to VS-41. Not unusual at all, VS-42 had TBDs assigned during a May 1941 cruise. VT-4 was, indeed, formed on 10 Jan 42. To quote Robert Cressman in his USS Ranger - The Navy's First Flattop from Keel to Mast - 1934-1946: "Subsequently, VT-4 (with its six Douglas TBD-1s) was formally activated aboard on 10 January 1942, under Lt. Wallace A. Sherrill, who had been flight officer in Scouting Forty-One. For the first time in her career, the Ranger had an operational torpedo squadron, which expanded her capabilities and allowed more flexibility of employment." (page 178)
Cressman, of the Naval Historical Center is author of such works as That Gallant Ship - USS Yorktown (CV-5), The Official Chronology of the U.S. Navy in World War II, and A Magnificent Fight: The Battle for Wake Island. He co-authored Steady Nerves and Stout Hearts: The Enterprise (CV-6) Air Group and Pearl Harbor and "A Glorious Page in our History" - The Battle of Midway 4-6 June 1942 (probably the best treatment of the Battle from the US side you can get).