i have a turbo 400 with manual valve body with pattern p-r-n-d-2-1 and when i have it in 1st and im driving and i go to hit it into 2nd it doesnt shift, then when i go to hit it into drive it goes into third. but when i leave it in drive it goes through all the gears very smoothly. people told me it could be the shifter linkage or low tranny fluid. anyone know what’s going on? thanks.