It's possible the shift linkage is out of adjustment on the car. If the 2-3 fork is not at the neutral position, the interlock may not allow the 1-R to shift properly. The problem could also be worn or damaged parts. Here is a link to a 1946 service counselor with a quick adjustment check procedure. Use the one for Clipper as it is very similar to your car.
https://www.packardinfo.com/xoops/html/downloads/SC/SC-VOL20NO5.pdf If adjustment does not do it, then there is a transmission and overdrive training manual or the section on trans and overdrive in the service manual (both available in the service, shop and training manuals section of literature) which will give much information on service and operation of the trans and some various symptoms and things to look at to correct a problem.
As you have overdrive, some problems there could also prevent reverse. Does the shift lever move an amount about equal to second where it should go into reverse but nothing happens or does it seem to jam or stick in it's travel to the reverse position. Many have experienced problems with the sticking and have found a lack of lubrication. There is a small hole in the gear shift tube in the area just above the shift levers exiting the tube near steering box. A few drops of oil in that hole has helped.
This Post was from: https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=73520