is this normal i have a 84 Ta with a 3:73 posi and it likes to whine. Is that normal, someone told it was but is it?

Some whine is normal, while other times it's bad. Depends on the wear/mesh of your gears. My old rear whined since the day I put it in the car, raced it a season and a half before it let go-was really howling which made me tear the cover off and see what I saw Got the new/used rear in there, this one is a 3.73/posi and is very quite.
Pull your cover and check the teeth for broken or missing ones and if all looks fine, try this cheap easy trick-when adding diff. fluid, substitute 1 bottle of the usual stuff for a bottle of the Lucas oil stabilizer. My old rear I tore apart and found 11 teeth missing was howling terribly, I still reinstalled the cover and threw in 1 bottle of syntec 85W Valvoline and 1 bottle of Lucas-took it around the block and could hear absolutlely nothing-that big of a difference. Definately worth a try.