Power Train Driveline problems of the 2010 Nissan Titan

Own a 2010 Nissan Titan purchased may 2010 from priority Nissan in colonial heights, va. The truck as begun to produce a vibration in the front steering traveling through the floor board and under the seats to the center of the vehicle. The vibration is stronger at speeds between 25-40 mph and when braking vibration intensifies. Took to the dealer on 2 Dec 2010 and was told that they had to order some parts to place some metal shims between the rear leaf springs and the rear axle. I strongly believe that the source of the problem comes from the drive shaft of the vehicle and expressed my concern and was told that they would place the shims first and go from their. It has been two weeks since my complaint to priority Nissan and I am still waiting for the parts to come in and the appointment. I am some what restraint from driving my truck on the highway at fast speeds do to this vibration with the fear of the drive shaft components failing and something breaking off. I found some complaints on mycarstats. Com stating that the source of the vibration comes from the propeller shaft u joint and that it should be inspected with the propeller shaft removed and replaced if abnormalities are noticed in the u joint. Some one needs to investigate this matter and have Nissan do a recall on the 2010 Nissan Titan. My truck is only 7 months old and only does city driving. No reason for the truck to be having vibration problems with out punishing the truck on off road driving.

Differential oil fluid found on left rear rotor cover and right rear rotor cover and on rear axle near breather valve and axle hub area.