loose differential?

[slash09]

I had an axle out last night and when I was turning the ring gear to take the c-clip out the diff was so loose I could move it a 1/4" back and forth ( in relation to the car) I checked the bolts and they were tight. This is the first time I've messed with a rear end. Should it be this loose? My Haynes manual doesn't say anything about checking it or taking it out even. It hasn't said anything useful about anything else I've had to work on either. WASTE of $20 for sure!)