Jeep Liberty Drive Shaft Replace/Remove

Replaced Plugs And Has A Ruff Idle And When I Put Car In Reverse It Makes A Clank Noose In Drive Shaft Or Rear End

My Local Mechanic Told Me That While Replacing The Transfer Case Switch (because My Part-time 4wd Light Was Turning On While Lever Was Down...

2002 Jeep Liberty 4 Wheel Drive Needs Drive Shaft Replaced. Quoted $960, Is This Reasonable. Live In Shakopee, Mn Suburb Of Twin Cities