Squealing/rattling sound when accelerating from a stop ('79 C-10. 350, TH400)

[jwjones]

When I press on the gas from a standstill and start moving, there's a good amount of squeaking/squealing and also a bit of rattling.  When I take my foot off the gas, those noises go away immediately (until the next time I step on the gas of course).  The sounds also seem to happen a bit when I'm slowing down to a stop and the auto trans is downshifting.  If I step on the gas and rev it when parked, it doesn't make the sound... just when the truck's in gear.

I've tried googling the symptoms only to come up with a thousand possible issues... Hoping someone here will recognize the issue I'm dealing with here.  At first I thought it was just the speedometer cable making all kinds of noises, but I disconnected it at the tranny and the noises didn't stop at all.  Anyone have a hunch what's wrong?

Thanks.

[FlatBlack77]

any chance you can take a video or a sound recording?

[jwjones]

I can certainly try!  Will post to this thread with a video or sound recording asap.

[K20Detroit]

It does sound odd, due to when it happens.
Until we have a sound clip, all I can really say is;
Check belt tensions
Check power steering fluid

[jwjones]

My mechanic's guess is the carrier bearing on the driveshaft, but he hasn't heard the sound yet and is just going by my description like you guys.

I am going to get a recording of the sound this weekend.

[Irish_Alley]

it might also vibrate when going bad but theyre easy to replace and most times if bad if you get under the truck you can move it a good bit

[jwjones]

edit:  Turns out it was the u-joints.  Who'da thunk it.