How difficult is it to change the universal joint?

the rear drive shaft universal joints should have grease ******* but someone in the past may have changed one or more with sealed joints you need to look to decide jack up the car remove out of P release handbrake rotate rear wheels and check the universal joints for grease *******

You have front wheel drive & CV Joints,
not U-Joints ,is that not correct

CV Drive Axles in front wheel drive vehicles
are just replaced as a complete axle assy

Ratchet, 3 or 6 inch extension, universal joint, and 3/4 inch or 19mm socket.
The plug is on passenger side of radiator on the engine side. The socket fits over the drain plug, turn counterclockwise to open or remove. On a Cirrus, it is difficult to reach, so I had to use a universal joint to reach it. I think the manual calls for a 19mm socket-mine was rounded off-a 3/4 in. socket worked.

When you replace the bearing you have to make sure the universal joints are lined up. Look at the front shaft, the way the universals joints are located, when you put the rear shaft on the the shaft/ universal joints have to be aligned. Also if there is any play in the universal joints they need replaced

If all is fine when moving in a straight line - you are probably OK. Turning while in four wheel drive, especially a full hard over turn, puts a great amount of strain on the universal (or CV) joints of the steering axles. Although CV joints are smoother they too still have to supply power to the steering wheels at an angle while turning. If you have concerns about the CV or universal joints, jack up your vehicle, secure it with blocks at the wheels and put on jack stands, then inspect the joints checking for excess play. Rotate the front tires back and forth by hand while watching and feeling for unnatural movement or obvious broken joints. They may be difficult to see if covered with a rubber boot. If you do have boots, they need to be in good shape since they are designed to keep dirt out of the joint. If they are not in good shape, broken or split, they should be replaced. Let me know if this helps. Thanks

known problem with altimasusually steering universal joint near firewall easiest fix i found white grease spray on joint this has lasted several years for me

Jack up each wheel and spin it by hand. When you hear that noise that will be a very worn wheel bearing on that wheel that needs to be replaced

you can use a universal joint extension and a wobble drive extension to get to the difficult ones

You have c/v joints not universals...first you need to figure out which side is making noise, generally you will find a torn boot around the bad one....Job is not terribly difficult, best to get a chilton or haynes manual for our car to guide you through it, if you haven't done lots of work like this though. Complete axles are easier to do and not very expensive (depends on car) shops set their own hourly rates so it largely depends on what the "going rate" is in your area.

There is a strap around both joint end caps on the differential end. unbolt them and then unbolt the flange that holds it onto the transfer case. Mark the slide joint at the center so you can put the two halves back together if it comes apart, (must be exact)
You can find instructions for doing joint replacement in any decent manual (some are as little as $20) It's not terribly difficult (I've done one five miles back in the woods with basic hand tools...Yes...i carry an extra in my box of emergency stuff at all times!!)
good luck!!