I don't think you need to pull the U-joint.
I would definitely pull and inspect the driveshaft as well as inspect and lube the pinion gear.
Here's what I think about the pinion... debate welcome...

A small amount of moly grease (not paste) is called for in the manual - they list an amount by weight, I don't
have anything that will weigh a dab of grease, so, small amount is an amount that won't end up clogging the
holes you see in the picture... the pinion is lubed by the final drive fluid, it comes in one of the holes and out
the other (they're different), and the seal that's there makes it a closed system.
-Mike