Thank you for posting your request on History Hub.
Technical Manuals would have been published as a part of the Publications of the U.S. Government (RG 287). Unless you have the specific Technical Manual [TM] number it is difficult to locate the content which you are seeking. Once you have narrowed the number down, then you can contact the Textual Reference (RDT2) unit of the National Archives at College Park, MD @ firstname.lastname@example.org.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RDT2. We apologize for this inconvenience and appreciate your understanding and patience
It may be helpful to take a look at the research guide created by the Library of Congress for United States Army Technical Manuals. To see if you are able to locate the number.
We hope that this information was helpful.
Thank you. I will have to poor over these to try to find it.