Got a 1986 302 F-150. It will randomly slip down to neutral when it's in first. It only seems to do it, if it does do it, in the first few minutes of driving. It's just when I'm going somewhere where I don't really leave first gear. It never just randomly switches to neutral in say 2nd or 3rd gear, it's only on low RPMs of first. Any ideas what this is or how to fix it? Thanks guys!

 

Sounds like a shift fork is bent slightly. Or one of those plastic things came off the end. That's what happend to mine. But it would pop out if I under revd a gear

 

As in it would shake the whole truck at low revs? Because mine does that too. Mainly low 3rd and 4th.

 

Yea if I was doing like 15 mph in 3rd and trying to accelerate the truck would jump around and knock itself outa gear.