1978 F250/ odd noise

[Evan's f250]

I have a 78 F250 with a 400 and C6 that I have just now this week got on the road. anyways, I bought it 8 or 10 months back and drove it home, when it had been sitting for a while. It made this same noise then, but was much worse then. anyways, when I was driving on the way bk home then, it made an odd noise at low speed. I put some tranny fluid in it and it got much better. it now still makes this noise with new fluid and all. right now it does it when u go from like 50 mph to 40 mph, then when u put on the gas and it gets to 45 mph, it makes a whoorling/odd sound from underneath, it stops doing this sound when the truck is back up to 50 mph or higher. it really only does this when u let off the gas and get right around 45 mph. Im geussing its the tranny, but it doesnt really slip or anything, shifts pretty firm. Maybe put some lucas stuff in there? The truck also has auto hubs, so I didnt know if it could be the front drive shaft?, but i doubt it, since it did better b4 by adding tranny fluid, or mayb it just got better as it got drove more?

Thanks in advance,
Evan

 

[Mil1ion]

what does whoorling mean ?

Do you mean a whirling sound?

Could be a few things, possibly U-Joints or Rear end gears,

THis is one of these things where a person actually has to be there.

how much fluid is in the trans ?

 

[78F250]

Hard to really say.

 

[Evan's f250]

trans is full, drove it more today thru town and all, it seems to be the u joint/knuckle jount on the frnt passenger side and or both the hub on the pass side along with the u joint/knuckle joint on the front passenger side, I can tell the u joint/knuckle joint on the pass side of the front end is wore out, and the pass side hub was hot to the touch. today was the only day i actually drove it at low speeds(thru town 35 mph and under) well it makes a horrible sound at these speeds. it runs out fine and dnt make noise at regular highway speed.