Whining noise 55-65 mph

I have an 08 Prerunner, 2.7 & 5 speed manual. I have a high pitched whining noise only in 5th gear between 55 & 65 mph. It's not noticeable below 55 or above 65. I've search this forum & Google but haven't found anything that addresses this problem. Not sure if trans, u-joints, carrier bearing or rear. U-joints & carrier bearing are original to my truck. I have 104,000 miles on the truck.

 

If it does it only in 5th I am thinking trans, Does it do it in 4th at that speed? Have you checked trans fluid level? U joints and carrier bearing don't know what gear your in, just speed so I doubt its those

 

Thank you for the reply. I haven't checked 4th but will today. Truck has been serviced at the Toyota dealer all along. For what it's worth, their checklist says fluid level was fine at 100k service. I'll verify this myself.

 

Mine does it as well. 5th gear is a pronounced whine vs 4th at the same speed/RPM. It drives fine and I replace all fluids and regularly check them myself. My carrier bearing was replaced recently with no change in pitch or sound. All u-joints are greased every second oil change and do not have any obvious slop.

The clutch on these trucks is a noisy bastard so I wouldn't be surprised if that sounds is coming from there.

I have read many others on the board saying that their truck does the same thing. I wouldn't sweat it too much.

 

Thank you JL911. I'm going to change my fluid & not sweat it. I haven't noticed any slop in my u-joints or carrier bearing. Mine drives & shifts fine. Thank you again.

 

Does your drive shaft have a 'double-cardan' type joint ? If so, make sure that all zerks got lubed. There are 3 zerks (not 2) on that joint, and the middle one is easy somewhat hidden and easy to miss by an inexperienced mechanic.

 

I have a prerunner, so unfortunately I don't have zerks that can be greased.