1968 F100 stuck in 1st gear (3 on the tree)

Hey man, no idea if my issue is the same but my 63 f100 with a floor conversion gets stuck in 2nd if you don’t properly follow the H pattern. go under the truck and see if one side of the linkage appears to go farther than the other side even though they should be aligned (if you have your car in what is usually neutral) if you are on a flat surface, you should be able to pop the gear out by hand. the only permanent solution i’ve found to this is strictly following the H pattern in the future. Hope this helps!