U Joint? 03 Silverado 1500 4wd.

Hey guys, I have a 2003 Chevy Silverado 1500 5.3L 4wd with a 4" suspension 3" block lift. I have been having a ticking sound bad coming from the undercarriage at speeds typically between 20-35/40mph for the last month and it is getting progressively worse. The best way to describe it is that it sounds like a "Stick in a Bicycle Stoke". I just had a Transmission replaced about 2 months ago. I am near convinced it is U-Joint or something related, however a family member keeps attempting to convince me that it is not even possible and that they have had many vehicles have the drive line play that mine does.

I'm just curious on some advice before I start looking into things. The family member is convinced that it has to do with rear end. I've replaced the differential gears two times so we're on the third set. I have no reason to believe that it is differential gears at the moment and they never sounded anything like that.

Year, Make, & Model: 2003 Chevrolet Silverado 1500 5.3L 4WD 4-inch suspension lift, 3-inch body lift

Recent Repairs: Transmission recently replaced (driveshaft was pulled during service)

Primary Issue & Symptoms

• Driving Noise: Loud, rhythmic, speed-dependent ticking/clicking noise coming from the rear between 20–40 mph.
• Under-Truck Inspection: Visible lateral (side-to-side) slop in the rear U-joint cross pin inside the bearing cap at the rear differential yoke, while the outer strap/bracket remains bolted tight.
• Other Known Suspension/Brake Issues: Confirmed that the rear brakes need to be replaced, and the rear passenger-side shock absorber is completely blown out / shot (internals feel gutted).

Differing Opinions on the Cause

• The Shop: Diagnosed the issue as loose leaf-spring U-bolts, but a physical inspection shows the U-bolts are fully torqued and completely tight.
• My Family Member: Bets money it's an internal rear-end issue. He believes that if it were a U-joint failure, holding the outer bracket while moving/rotating the driveshaft would show independent play or wiggle room between the bracket and the shaft. Since holding the bracket causes both to move together as one unit, he isn't convinced it's the U-joint.
• My Observation: The strap holds the outer cap locked to the pinion yoke as designed, but the internal needle bearings inside the cap appear disintegrated, allowing the cross pin to slide around inside the cap space underneath.

1. Does the attached driving video sound consistent with a failed rear U-joint under load?
2. Does the video of the driveshaft play confirm a blown U-joint, or could this movement actually be coming from an internal rear-end / pinion bearing issue like my dad thinks?
3. Is it common for a worn U-joint to fail right after dropping the driveshaft for a transmission job?

Sound at Speed

Drive Shaft Play