Upper bushings on an 8.8

Get a set of urethane bushings and use a drill bit to "walk" the old bushing out. Most urethane kits come with instructions for removing the old bushing. Basically you drill into where the bushing meets the ear on the rear end, and start drilling, that should cause the drill to basically go in circles around the inner edge of the ear, causing the bushing to be pulled out.
 
I replaced mine. Actually I had DTS do it when they built my 8.8. I noticed the old ones were completley rotted, I could almost pull the center dowel out of the rubber!!! Do what was suggested above, also if you have an air hammer that will work too.