transmission issue?

[71f100351c]

I have a 1971 f100 with a 351 Cleveland and a c4. The motor has been rebuilt but the trans is quite old and.most likely from 71 or.somewhere around there. After getting the engine installed I drove it and it.ran and shifted fine. One day I drove to a friends house and back and I was about a mile from home and going up a hill.and the engine started cutting out and died like it was starving for.fuel. I got the truck home thinking maybe something got in the fuel line or something but I started it back up and it ran perfect. I drove the truck around some more here and there and took it about 50 miles to get aligned it ran and shifted perfect and I had no problems. About a week later I decided I was going to drive it to school and I got a little ways down the road and it started the same spuetter.and died again like something forced.the motor to die. I started the truck back up and it idled and revved up fine. When I put it in drive it drove through first gear fine, but when it got to second it was like every time I touched the gas it would sputtered and die. I can't figure out the problem, I have replaced the modulator valve and the vacuum line going to it and checked the fluid. Everything seems to be fine. It only does this in second gear, and I never get the chance to get to third due to it dying or sputtering when I touch the gas. Any suggestions? Do I need a new transmission? Any help would be greatly appreciated

[Donnie]

It is more likely a fuel or ign problem........does NOT sound like a trans problem to me..Donnie

[gleno]

Water vapor condensing in the fuel tank and icing or water at the bottom of the tank being pumped into the carb bowl? This is a possibly, because it is winter. Did someone put a piece of Saran Wrap in your fuel tank for a joke? Someone did that to me, and every time the Saran Wrap would plug the fuel pick-up point, the engine would quit. It took FOREVER to figger it out. Statistically, you will expect to find an electrical problem that is shutting you down, so chase the usual suspects like connections, and rule out lack of spark. And if anybody on this site lost their pride and joy truck in a divorce, don't you DARE put the wrapper from the last lunch your spouse packed you into the tank.

[BobbyFord]

...Did someone put a piece of Saran Wrap in your fuel tank for a joke? Someone did that to me, and every time the Saran Wrap would plug the fuel pick-up point, the engine would quit. It took FOREVER to figger it out...

My dad taught me that one