91 caprice back end. please help

I need a new back end i guess, i have no idea where to start. I took my car to sears to get a differencal? service something like that and ever since then there is this high pitch sound coming from the back end please help..

If they changed your rear end fluid, I would check and see if there is enough in it. if so then your bearings might be grinding(hence the noise) and probabaly need replacing.

If they changed your rear end fluid, I would check and see if there is enough in it. if so then your bearings might be grinding(hence the noise) and probabaly need replacing.

i check the fluid there is alot. there is a lil hole i stuck my finger in the side and i can feel the fluid(not a hole, there is a cap there). what is the bearings the big gears inside?

i check the fluid there is alot. there is a lil hole i stuck my finger in the side and i can feel the fluid(not a hole, there is a cap there). what is the bearings the big gears inside?

Idk really, there is engough fluid in it, if you can feel it.

Sorry, Im not a real expert, maybe one of the more smarter people here can help.

My guess was low fluid burning up your rear end, but that doesnt seem to be it.