Rear hub bearings should turn freely. They should not feel "sticky". Under normal usage, they also should never need repacking. The way the rear hub is designed, repacking would require the same effort as rebuilding.
Last fall, I replaced the bearings in the right rear hub of my GT6 last Fall. It is not a job for the unequipped or faint of heart.
First problem was rigging something to hold up the car. The shop manual provides drawings for fabricating a tool to hold up the car while working on the hub. Not wanting to spend time welding and fabricating the shop tool, I used a 36" long piece of 2" pipe bolted to the spring with three 3/8" diameter 2" wide u-bolts. All these items I purchased at Ace Hardware. After bolting the pipe to the spring, I jacked up the end of the pipe as per the manual. The bar holds the spring at more or less ride height and the hub hangs from it.
Next problem was extracting suspension bolts that had rusted in place (I never did get the lower pivot bolt out of the hub carrier). I disconnected the half shaft from the differential hub and the entire assembly came out.
To get the hub apart, I used a gear puller and my shop press. The hub came out with about 2-3000 lbs pressure if the press gauge can be believed. Whatever pressing force may be required, it is clearly beyond the capability of any mechanical puller.
There is a distance piece or shim in the hub that sets bearing clearance (again, see shop manual). I opted to try the new bearings with the old shim to see if I could get lucky and as it turned out, proper clearance was achieved. I had to use the press to put the hub back together. It required 6-7000 lbs pressure to bring the hub together. There isn't a hammer big enough to bring that kind of force to bear.
The whole process took up my evenings for about 10 days. Unless you have a pretty well-equipped shop, you might want to take your car to a professional who knows what is involved. Ask questions to make sure the mechanic really knows what he is doing.
Good luck.