transmission vs transmittal

transmission and transmittal both are nouns.

Word	Noun	Adjective	Verb	Adverb
transmission	Yes	No	No	No
transmittal	Yes	No	No	No

As nouns, transmission and transmittal are synonyms defined as:

transmission and transmittal: the act of sending a message; causing a message to be transmitted

Other synonyms of transmission include transmitting.

transmission (noun)	transmittal (noun)
the act of sending a message; causing a message to be transmitted	the act of sending a message; causing a message to be transmitted
the gears that transmit power from an automobile engine via the driveshaft to the live axle
communication by means of transmitted signals
an incident in which an infectious disease is transmitted
the fraction of radiant energy that passes through a substance