I bought a 96 F150 5.0 automatic 4X4 on craigslist [long distance] and sent a buddy to pick it up. The 4X4 low light is on even though the truck is in 4X2 high. Truck won't shift into O-D. Cruises along ok except at interstate highway speeds, when the engine is rather busy. This is a floor shifted transfer case not electric. Any common problems to look for?

 

Sounds like two separate issues to be honest. The first is probably a wiring short in the pigtail to the transfer case and the second is that your transmission won't shift into OD. Did you actually count the shifts? It's a four speed automatic and you should be able to feel/hear/see (if you have a tach) each shift. Does is have an OD cancel switch? It could be tripped or shorted. Again, perhaps a wiring problem.

 

This truck is still 1100 miles away, but my friend counts two shifts. Just wondering if there was an electronic lockout that prevented O-D while in 4X4 low.

 

What I meant was: while it THINKS it's in 4X4 low.

 

It's possible, so you may be dealing with one problem. Maybe someone with a similar truck will chime in. I never had my truck going fast enough in 4lo to find out.

 

My 95 F 350 diesel will use OD in 4WL. My T-case selector is frozen and wont go in Low on my 95 F 250 5.8. So I cant even tell you on that one but I think it would.

I think you have 2 issues also

 

I don't think there is any mechanism that prevents the transmission from going into OD in 4low.. especially with a manual t-case. So either your truck doesn't have an overdrive transmission or it's got a sensor issue. Any flashing lights on the dash? Does the speedo work?