Contact a couple of Freightliner dealers and get quotes for the job. There are flat-rate times for this type of work. Example: a 4700 series International with a DT466 and a 6 speed paid around 4.5hrs. labor to R&R the clutch.
You might want to contact a couple of indie shops for quotes as well.
When you have gotten the quotes and decided which shop is going to get the job, be sure to ask for the estimated completion time when you make the appointment to have the work done. They should have the parts in stock (or near at hand) and have it in and out the same day.
Extra work required...refacing the flywheel...replacing a u-joint or carrier bearing, etc. will add to the time required to do the job. Be sure to insist that you be notified before they do any work over and above the quote. Also, be sure that the shop has a way to contact you if additional work is needed!!!!!
Based on my experience, I disagree with RichM about the trans seals. If there are no leaks, don't mess with them!
Rex