Join Date: Dec 2015
Location: central new york
Spraying wd-40 might help very temporarily, but it likely make them go completely bad quicker (they are going to go completely bad no matter what).
I just did both axle u-joints and hub/bearings on my own this weekend. It is a job almost anyone can do, and there are plenty of how-tos on the web to understand the process.
The job books for about 1 hour per side to do the u-joints at a shop. So to do both is about $200+ (labor only). The shop I was dealing with allowed me to supply my own choice of u-joints. So it would have been about $250 after my cost for parts. If they force you to buy their parts, it will probably be about $300. It shouldn't be any more than that. (because it doesn't take more than an hour to do each side, and in fact they should be able to do each side in 30 minutes).
To do it at home, for the first time takes about 3-5 hours.
I rented a u-joint c-clamp press from the auto parts store. However, the next time I do u-joints, I think I'll skip that. It was almost more trouble than it was worth. I used the dead-blow hammer more than anything.