Assuming you mean the left rear tire is locked up, I would suspect the parking brake cable for the left rear wheel is stuck, probably from lack of use. Replacement of cable is necessary.
When the input shaft is locked to the intermediate/output shaft
i believe its a automatic friction lock if u don't have manual locking hubs
i was told its because they are for when you are parked only, and if you drive with them on someone could mistake that you're parked and hit you.
Drive or if you are parked, sleep.
If, as you state, the vehicle is a 5 speed, then I am not sure what you might have. If I recall, the manual tranny was a SM465 4 spd and the auto was a 700 R4. if the truck has over drive and is an auto it is a 700r4 if it doesn't and is auto it is a 350
Leave it parked and don't drive it.
Only if the diff is locked
The Ford F2 50 four-wheel-drive hubs will be locked when they are turned to the right. They will be online when they are turned to the left.
leave it parked in your drive way
Yes, but it will increase wear on the front part of the drivetrain, and also might decrease mileage a little. I only lock the hubs when I might need 4wd in winter.
When a vehicle does not go into gear when it is shifted from park to drive, it is usually due to transmission issues. If it has a manual transmission the gears may be stripped, if it is automatic then the transmission may have overheated.
People drive a manual car by using a stick shift to control the car.