Today as i was pulling a trailer home. I heard a squeal as i pulled away from a stop sign. Not sure what it was but i looked the truck over at home and found nothing. Later in the day I drove it down to my dads, (7 miles) all was well but when i got there as i pulled up to his shop and stopped It started squealing again....?? At this point we started looking it over again and this is what i know.

Truck is an 85 W350 crew cab, 360, 727. At idle everything sounds good in park and neutral. Put it in gear it starts to wine and squeal. but only in gear, forward and reverse. Jacked up the back tires. As long as the tires are turning no noise. As you start to apply the brakes it will start to squeal and gets louder as they come to a stop. IT sounds like its in the front of the trans/ converter area.

It sat for a few hours and I drove it home. It shifts firm and when it did it would chirp and make a small squeal that went away as the speed increased. on every shift. I put it in neutral and rolled into the yard with no noise. Hold the brake and put it in gear.... it starts squealing again. At this point I will park it until I find out whats wrong.

I think when the converter is stalling its squealing. Any thoughts on this? What could this be? Does this theory make sense?