Anyone that has read the various posts on this forum knows that finding the PROFESSIONAL to do work on your coach is very difficult. If you have an XYZ coach, and you pull in to an RV service center, they will assign a "mechanic" to work on your coach, charge you a huge amount for labor, even if this is the first time this center has ever seen an XYZ type coach.
The work may or may not be done correctly, but you will still get the bill. There have been many many posts about unsatisfactory work being done with some exorbitant labor charges. Basically you may end up paying for some low level wrench turner to get a little "on the job" training.
You best bet is to either research what needs to be done to adjust your wheel bearings, decide if you are capable to do the work, or find a truck service center that will work on your specific type of chassis. The research is important so that you can get some idea as to whether or not the service center is BSing you or if they actually do know what they are doing.