Not sure what they will charge you but would you be better off just bying axles? http://www.ringpinion.com/PartsList.aspx?SearchMode=Diff&TypeID=2&DiffID=107&Diff=Chrysler+8.75%22%2c+42+Case+Housing++&CatID=20&Category=Axle+-+Rear+(Both+Sides)
This is what I bought and they worked great.