Does your squeak have a rubbery sound to it? U-joints have a rubber dust cap, bearings don't. As bad as my ujoints were, I could never tell it by physically checking them on the truck, YMMV. Also, it's a given the ujoints will go bad, no way to grease them and they are exposed to the elements. A lot cheaper to replace ujoints as a tshooting step.
I highly recommend purchasing a hydraulic press for the job. I got a 12 ton el cheapo chinese one for $99. It made removing the u-joints sooooo simple. I didn't price the cost of having this done professionally, so it may be cheaper if you don't need a press around for other jobs. I personally have an odd job now and then that it's really nice to have the press for. You could possibly make a press with a heavy duty c-clamp and some sockets. Autozone has a free-rental ball joint press that might work. Otherwise a sledge hammer and a lot of cussing.
I jacked up the truck frame, for easier access, from the rear end using my tow hitch as support. Put a dab of paint on each piece to key the shaft. Took loose the four bolts going to the rear. Pried the shaft forward from the rear. It dropped, pulled it out from the trans, lost two tbsp. of tranny fluid.
Remove the ujoint retainers with screwdriver and pliers. The press has a plunger that was just the right size to push the whole ujoint through. The cap on the far end would break, so I turned it around to push it out the other direction and it would be free to remove. I used a 1-1/8" socket to press into, no damage.
You tap the new caps back in from the outside of yoke. You have to put the joint, sans caps, in yoke first and hold it into the cap while tapping it in to prevent the needle bearings from falling out. Tap it in all the way and put in a new retaining clip. Repeat, repeat, repeat.... Grease them up good and hit them again with every oil change.
Tapping the caps in is a real pain in the @ss. I dropped one of the caps and lost the needle bearings <sigh>, so had to get another joint. Might wanna buy three to be safe and take unused one back.