I didn't drop the tank on mine but probably should have. Mine was bone dry so I wasn't worried about mixing with the bad fuel. According to the PO, he drove it home and only had it for a year or two, so I figured it shouldn't have been too bad for rust. I'm pretty sure that there were some logic errors and a lot of laziness on my part thinking that made it OK, but so far so good. I got lucky and have had no issues with rust in the fuel filter or tank rusting through. Your mileage may vary. If you have to empty the tank of all the bad fuel anyways, I would just drop it and make sure it is done right.

After being lazy with mine, I recently had to help a friend drop a 3/4 full tank to change a fuel pump and we found a ton of junk in his tank. And it was a 96 and had only sat for a few months. The process wasn't as hard as I made it out to be and it worked out way better in the end because the pump wasn't the issue. Knowing the tank was clean and had 100% good, fresh gas eliminated a lot on the troubleshooting later.

 

I replaced the fuel lines and added a extra fuel filter by the rear tank. After that she started right up! A lot of white smoke! I let it run for about 1/2 hour and still white smoke. What could that be from? See photos.

 

 

Hell yeah! Congratulations! The smoke doesn't look that bad. I'd probably give it a chance to run and drive, and see if it clears up.

 

 

Congrats on getting it running. Looks like the ol boy just needs to get the cobwebs out of his lungs. Looking forward to seeing it all detailed.

 

 

The shift collar broken seems most likely.

Shift collar videos (3 part video for a Bronco- very similar to F-series):
The shift linkage could be disconnected at column end or transmission. This should be easy enough to spot visually. A badly slipping tranny would be the only other likely option. Check the fluid level and make sure the fluid is not burned. Other less likely options could be a disconnected driveline, stripped rear yoke, or differential issues.

 

 

 

 

Well if the linkage is moving at the transmission, you are correct- the collar is good and linkage is connected. When going through the gears, can you hear it even try to engage and does the driveline at all? Speaking of, since you were under the truck I would think you would have seen a disconnected driveline, but it never hurts to ask. So far, it seems to me the next most likely suspect is the transmission. Did you check the transmission fluid level and smell it to see if it smells burnt?

 

Did you check the oil level on the transmission? Maybe the vacuum modulator has a hole in it sucking ATF into the engine making it smoke...Or your smoke could be bad valve guide seals.