driveshaft and rear wheels turn hard
If it's been sitting for a while, the outer axle bearings could be seized/tight from sitting, moisture, no grease, old grease. I just took apart an 8 3/4 and the outer bearings were rusty and extremely hard to turn, caused by bad seals and old grease. Like chasduster also mentioned, that suregrip could be stuck also from non-use!! Good luck with your project, Geof