straightsixjeep

CF, I need your help. Iv already made some threads about my jeeps rearend making a clunk sound, however its getting worse. Its a 98' cherokee sport with the 8.25 rear end. Since I bought it one month ago, when I shift gears and release the clutch or when I give it gas after coasting, the transfer in energy creates a clunk in the rear end. At first, If I eased in and out of shifting it would be a faint clunk, but now it makes a very loud clunk when I give it gas or shift. I pulled the diff cover and saw no metal shavings so I resealed it and topped it off with 80-90 weight gear oil. I was thinking my sagging leafs and cracked shackles might of been rubbing so I replaced the leafs with heavy duty crown leaf packs, new rugged ridge shackles and new u-bolts. I replaced those 3 things last night, and now Im getting a vibration/hum around 40-45mph and another weird noise from the diff at that speed. Its almost like a low pitched rattle, hard to describe. I can only hear it when Im on the gas, when Im coasting that new rattle sound goes away. Tires were replaced 2 days ago, it still made the clunk but it was a very smooth ride. However, after changing the leafs, shackles, and u bolts last night Im getting the hum/heavy vibration. Everything was torqued to specs, and I had an ase certified mechanical check my work. Im thinking all of this has to do with the differential. A week ago I jacked the rear end up and tried spinning the yoke back and forth, there was some play. I did the test again today and there seems to be even more play. Does the clunk, vibration, and low pitched rattle at 40mph+ all sound like possible spider/side gear wear? I just purchased an aussie locker so I can replace the gears, do you think that will solve all my issues? This is driving me nuts, I dont even want to drive it until I get this figured out. Please please please let me know what you think. Thank you