Rumble when deceleration

[Perspective]

My 06 Liberty auto with 241,000 miles just started making a new noise. It only occurs when I am decelerating and seems like it's about to downshift into 2nd and then again before going into 1st. When it gets close to down shifting into 1st, it also give a shake/shutter that you can feel. The sound is similar to engine braking in a manual.

Other than that, it seems to drive fine and shifts smoothly going up through the gears. This only occurs when slowing down.

Any thoughts? Would ****** mounts cause this? U joint? ****** going bad?

 

[KJowner]

Is there plenty of oil in the gearbox? Is it still nice and pink? If it's brown or black the clutch packs are slipping.
Start with the cheapest part after checking the oil, the front prop UJ, is the small rubber boot still in place? If not the joint is probably wrecked. You can completely remove the shaft for a test run, and the joint is cheap + easy to replace.

 

[Perspective]

So the gearbox oil is pink. The small boot coming out of the transmission on the drive shaft going to the transfer case is torn and there is definitely a little play. Looks like I'm starting there.

Any recommendations on where to purchase the kit for the front driveshaft? Rather not buy an entire driveshaft.

 

[Perspective]

UPDATE: I removed the front drive shaft and there was improvement. The sound is not as bad. The sounds come during deceleration at 55-45 and then again around 25. The vibration is really there anymore. It feels like there is a drag on the jeep and sounds like a faint engine braking.

The front drive shaft definitely has play on the transmission side.

The only thing that may be related is I recently did the rear brakes and afterward, when slow moving in a parking lot, there would be a rubbing sound/metal sqeek. I even replace the sliders on the calipers as they were rusted/frozen up.