Hey everyone. I have a 77 F-100 with a 302. When I bought it, she needed a transmission, but cranked and ran fine otherwise. After yanking and putting in the rebuilt transmission, it would crank cold and run fine but after running for 20-30 minutes and being turned off, she will not restart - and it DIDNT do that before the transmission was removed. I mean won't even hit a lick, which is to say when the key is turned to crank it, it's just silence. No clicking, turning over or anything. And now the ole girl won't even crank or turn over cold - still silence when the key is turned... So far I've thrown cheap parts at it which would be a new solenoid, starter, and ignition coil. I also tried a new ignition module to no avail. The battery is good along with the alternator. I've also sanded all grounding wires and frame where they connect. It doesn't make sense to me why it's happening after putting a rebuilt transmission in. Anyway, any and ALL advice or ideas will be greatly appreciated. Maybe a new lock cylinder? I've got no clue what to try or test next. Thanks for reading. Keep her between the ditches.

 

How long was it down during transmission replacement?


At this point, you're saying it will not even crank, nor do you hear the solenoid activating when turning the key? Do you have a bump-switch that you can hook to the solenoid to test the starter circuit by itself w/o the ign. switch? Have you checked all fuses? If you don't have one, I'd pickup a copy of the wiring diagrams, with that, a decent multi-meter and pin-outs, you can test your existing ign. switch before throwing money at it.

 

I don't know if your rebuilt trans has a Neutral Safety Switch on it or no....not sure of the years they came out on but mebbe it's worth a look see?

Also, does the trans "click" into the various positive stop locations....P, R, N, D, 2, 1?
That could need adjusting.....

 

On my 77 the nss was at the bottom of the steering colume.

 

It was down about 2 weeks for the rebuild. And the solenoid wont even click when the key is turned. And I don't believe I have a bump switch, I'm not exactly a car wiring virtuoso.

And​​ it does click into all the gears and I'll look for that neutral safety switch.

Thanks fellas. Any other ideas are welcomed.

 

If it isn't the NSS, I'd guess you missed a ground strap somewhere or it's not connected in a useful way.

Battery negative goes to engine block so starter gets as much current as it needs but you still need to ground the cab and frame or none of the accessories will work right or even at all.

I cleaned the battery negitive cable at both ends which improved my poor hot start then replaced the battery which completely fixed it. Battery tested good with cheap Harbor Freight tester but didn't have the pop to spin a very tired 390 unless it sat for half an hour.

Wiring diagrams are here. There aren't any for the '77 but you can compare the '76 and '78. Basic things like starter wiring didn't necessarily change year to year.

Michael

 

I had the same, almost exact problem. Sometimes it started instantly, other times it was dead, nothing. I figured out all I had to do was move the shift gear selector on the column a little towards reverse and it starts, my guess is after the install the safety switch probably went out of alignment

 

Don't throw any more parts at it for the moment. Sometimes that's all you can do, but there are some things to check first along the lines of what the others have mentioned.

And just FYI, nothing in the ignition module will keep the starter relay from clicking or the starter from cranking.
So keep the old one as a spare.

Second, new starter relays/solenoids can be absolute crap! So do not rule out the new one as being bad. It's so common in fact I would never trust one without testing it first. You could be chasing your tail for days only to find out that the new part was no better than the old failed part it replaced.
But wait! There's more!
Keep the old relay for now as a spare too, because there are other things it could be.

The Neutral Safety Switch could be bad, OR it's wiring could be suspect.
Not sure if it's the same on a '77, but if yours was a later build you could have what became the '78 wiring scheme.

For for now a few questions:
1. This is a 2wd presumably? With a 302 I think it has to be, but figured I'd ask.
2. Find the NSS and see if it's on the lower end of the steering column (under the dash) or on the side of the transmission itself.
3. If it's a manual transmission, look for a connector for the NSS and see if there is a little Red w/blue jumper wire between two points of contact. I don't know how they did '77 2wd trucks, but the '78 4wd's would have had one. The jumper, or it's connector often fail at the most inopportune moments, and also leave you chasing your tail.

How do you know the battery is good? Have you load tested it? Load or not, I suppose if it's showing 12v with a meter you should still get a click.
Some tests to perform (with caution) while you're at it then:

1. Find the small Red w/blue wire at the starter relay and disconnect it. Make a jumper wire, or just use a screwdriver like so many do, and touch the main battery cable side of the relay to the small "S" terminal you just removed the wire from.
If you get no click now, you either have a completely dead battery, or your starter relay is toast.
If you get a click and your starter spins, then something is keeping the power from getting from the key to the relay. Time for more digging.

If you get a click but the starter does not spin, then use a much bigger jumper tool to connect one large lug of the relay to the other (battery direct to starter) and see if it spins then.
If it does not, then either your battery, your starter cable, or your starter are bad.
If it does spin, then your relay is bad.

All this is done with the greatest of care of course, or you could end up running over your toes and your neighbor's roses. In other words, since you're messing with starter stuff, make sure it's in Park/Neutral, the brake is on and/or wheels chocked, and the key is OFF so that the engine won't start if you get the starter spinning.
Common sense stuff, but if you're new at this and under pressure to get things going, that stuff gets ignored sometimes.

Other tests and stuff too, but for now that should get you somewhere.
If you buy another starter relay, get a good (more expensive) one or grab one out of the junkyard.
If your battery and starter cables are old, sometimes that's a part you can just "throw at a problem" without worrying about justifications. Sometimes they just need to be replaced. They do a lot of hard work after all.
But since you did not mention any lack of power to the other things on the truck, presumably at least the battery cables are still good. But if the starter cable is bad, you'll have power to everything but the starter.

Good luck.

Paul

 

I,m just throwing something out there. Are you sure that the torque converter got seated properly? Can you turn the motor at the balancer? The reason I ask is years ago in my rookie years this happened to me me, altho the engine and trans came together as one the convertor wasn,t seated and the engine was stuck.