I am looking for a manual for a TRC 474 CB Radio (not a 447)

Go to www.cbtricks.com on the left side of page go to radio schematics and manuals.Click it.You now have the radio information page. In the center you will see the alphabet,click on the "R" the fourth radio down is realistic,click on it. this page is for all realistic radios.Look for the radio you need the information for and click on it. It opens to the manuals of owners,factory service and schematic. When you click on service manual you will get all the information you want.

What do you need to know about it

Here is a schematic for the TRC-474