My son has a 69 F250 (Camper special 2 wheel) with a rebuilt 390...he took it to the shop for some rewireing. Got it home and now the tranny won't shift into third. It hardly does any shifting now...ideas? Not real familiar with this tranny, any ideas on which tranny it could be as well, maybe I can find another at a local yard.. shold be too hard to replace.. he did replace the neutral safety switch as well

 

There should be vacuum hose or tubing that runs from the vacuum modulator to the intake manifold. If the modulator doesn't get a vacuum signal, the transmission will shift late - way after it should. It's possible the vacuum hose or tubing was knocked loose during the work being done. The modulator valve is mounted on the transmission at the passenger side rear, just above the pan.

 

Transmission as originally equipped: C-6

 

Thanks for that valubale info...I can't wait to check it out..got my fingers crossed

 

valuable, even

 

I hope that's what the problem is - it's inexpensive and easy to fix.