My Navara (2007, 48k miles today) went into the former Nissan Dealer up here. It's part of the Evans Halshaw group, now only sells Renaults as a franchised dealer but is still an authorised service centre for Nissan.
Anyway, the car went in for replacement wheels under a safety recall. They performed a free 'safety check' which turned up that I needed a new front propshaft and all four driveshafts. Possibly rear propshaft too. Did I want to go ahead and do the work...... I declined but got the parts list etc.
Total price £1200 but if rear prop was needed (75% chance apparently) it was another £1100.
Anyway, I took the car away - against there advice as it was hugely dangerous apparently. I went to my mates garage and let him have a look. Driveshafts fine. Rear prop looks ok. Front prop dodgy (I knew this as I could hear it) so it'll need new Universal joints.
I went away and ordered two new universal joints for the front pop and got them delivered to my house by a 4x4 specialist for £38. My mate and I whipped off the front prop - a whole 8 bolts and 10 mins, he got the old UJs out, we tidied everything, greased them up and popped them into the propshaft. Bolted it back up and paid him a few quid for his time.
Moral of the story is, if you smell a rat then get a second opinion. This is the reason why I only use people I trust and would NEVER use the main dealer for anything.
Hopefully some happy motoring without big bills for me... fingers crossed!