My wife's Navigator whines on the freeway also, i think some vehicles just do it.

 

When I heard my whining from my rear it was my rear end going out......:O(

 

Typically a bearing or ring/pinion problem (worn teeth, backlash, preload). Whining is not normal.

 

Probably not normal, but I have heard vehicle's will whine for years and years without any issues (besides the annoying noise).

 

I dunno, I have always swapped them with junk yard rear axles because the noise made me crazy. I once had an old hipo mustang that I could change the pumpkin about as fast as most people change a tire.

 

bump:bump: bump bump it up :bump::bump:

 

I would be concerned if mine whined. You're past the 5yr/50,000 warranty, so having Nissan inspect the gears is a waste of time. I would take it to a reputable gear shop and have it inspected. If they determine the gears are badly worn, they can replace it with a Trutrac before total failure. The Trutrac installed should run about ~$800. Do a search on the forum, and you will find many threads covering part numbers and alternatives.

 

Not sure where you figure a Tru Trac installed runs $800. The Tru Trac alone is over $600. All research I have done shows closer to $1,000 plus.

The whining is not all that uncommon (not just a Titan thing) and does not mean impending doom. Mine has done it for years. I have talked to others with non Titans and they had no issues other than noise. Usually it is a ring and pinion alignment issue. My rear diff fluid changes show no abnormal wear or particles in the fluid to show the teeth are wearing out, just dirty gear oil. It is annoying, but I like my music loud .