Driveline clunk question - 6spd Manual

I have 2012 6spd that I picked up almost a year ago and it has always “clunked/jerked” in the driveline when you are on and off the gas. You can feel it changing gears sometimes. However, it is very apparent on and off the gas in all gears. Definitely a jerk/slop feeling. You can feel it and hear it. I know the manual will have some slop/backlash feel but this seems like a lot driving. I would assume this is maybe a pinion nut or pinion gear issue. The U joints don’t appear to wiggle any. Truck has 127k of very gentle use/commuting. It is to twist and the pinion moves slightly.

I Appreciate any help or suggestions from all the great minds here (much better than mine!). Thanks!

 

Check the torque on the rear axle u-bolts. They should be around 73ft lbs. Mine werent tight enough on my 2013 6 speed from the factory and i had a clunking noise as well

 

There was a tsb for a “clunk” caused by the rear output shaft on the transfer case I believe. Mine does it when shifting from park/neutral or reverse to drive. Also notice some lash when on off the throttle while driving which maybe in the rear end. Wouldn’t worry too much about it unless it’s a u joint