got my blazer runnin and took it to the river. started to spin and *pop*. there went the rear end. front wouldn't pull either. guess the front end was broke when i bought it cause i never tried the 4wd out before. no front driveshaft. well i put it in gear and let out on the clutch. nothing. 4-Lo both driveshafts are spinning. sucks.. my question is "how hard are the spider gears to change?" never messed with rear ends before besides changing fluid and brakes. not sure what i'm getting myself into. if it helps it's a 3.73 1/2ton.