I think my Trac-lok has had it

I recently had the back of my car on jackstands and I went underneath checkin the driveshaft bolts/ujoints. I grabbed both tires and with some force was able to turn them in different directions. Is this a sign of the trac lok worn out? Also if I spin the driveshaft there seems to be quite a bit play in the diff.(gears worn?). The rear does whine and it's the worst when cruising in 4th. My car in general just doesn't spin em like it used to and feels sluggish, I'm thinkin I need to have the whole rear looked at and rebuilt. BTW these are stock 3.08 gears, and I have recently topped off the diff fluid.

ttt

That's a bit pricey especially for me. IMO it's just not worth it to spend that much money on the rear end of my car. I can't do anything now cause I'm broke and in school. LOL My car's got some miles on it and I don't plan on doing anything to the engine anytime soon. I was leaning towards just gettin the stock trac lok rebuilt and/or new rear bearings/seals, and 3.73's. Hopefully keeping everything in the $400 range.