I am really new to my 1950 Ford F1. I have the flathead 6 cylinder with a 3 on the tree manual transmission. The transmission was rebuilt, but I am not sure everything is correct.

2 issues.

1. You can't gear down. I probably just don't understand this old a vehicle, but I am used to gearing down to reduce speed. It seems I would grind the gears off if I tried to do that in this truck.
2. Pops out of second gear. Yes I can hold the shifter up and it stays in gear just fine.

Anybody got any thoughts? Is this minor stuff or is there something not right with this transmission.

 

By gear down do you mean shift into first while driving? If so, no basically you need to come to a complete stop. First gear is not synchronized like modern transmissions. The very experienced and skilled can double clutch down into first on the move, but most of us just stop. Popping out of second is annoying and a sign of some wear, but nothing worth taking the transmission apart for.

Do you have any bearing noise in the transmission? If not, it is probably usable as is.

 

If it pops out of 2nd when accelerating, it's time for a rebuild. If it is when using 2nd for braking, like 38 said it's not uncommon but a sign of thrust bearing wear.

Make sure your clutch is properly adjusted too.

 

Popping out of gear indicative of worn 2/3 syncro brass blocker rings.

Ford type 3.03 3 speed manual ALL syncromesh trans introduced in 1963. Previous 3 speeds have a crash (non syncro) 1st gear.