Town car squealing

My towncar is making a squealing sound whenever its moving forward i took it to the mechanic for a diagnosis and he told me that I needed a new rear end that the gears are grinding and something about air suspension. I'm trying to find out what is the exact name for the part(s) that I need to buy so I can find a better deal. I got an estimate for almost $900 375 parts Labor $445

Car specs
1999 towncar
131000 miles

Hello, did you have the front pinion seal replaced? I did mine and forgot to remove the crush sleeve and it made a squeal noise for a while until I figured it out. Also, If your looking for air ride stuff, try suncore out of South Florida, they seam to have the best prices that I can find.

I also had that problem with TC and it was the front ball joints. Check those out also.:2cents: