can't locate the whine

I have a 2008 Tacoma prerunner that sounds like mudgrips whining when underway. i changed the wheels and tires and the front u joint. i can hear it, but not not nearly as loud, when running it up to 40mph with the rear tires off the ground. the build sheet says nothing about limited slip or locking differential. see attached.

my thoughts are driveshaft carrier bearing, axle bearings or rear end. any advice or suggestions would be greatly appreciated.

 

do you have a supercharger?

 

no supercharger

 

Is you diff fluid at proper level?

 

differential was 1/2 qt. low. filled it and it had no effect on sound. i can drive 25 mph, put it in neutral and kill the engine and it makes no difference in the sound. i did discover that the left rear axle seal is leaking, but the sound is no louder on the left side than the right (i rode in the bed and leaned over.) it is actually more noticeable in the cab than hanging out the window or over the side of the bed.

 

How about the carrier bearing. Any movement more an a 1/2"?. Also fix the axle seal. Might help if not don't rule out pinion bearing. Also check trans fluid.


Edit check front wheel bearings

 

When you had it at 40mph on the jack, were you able to listen with a long rod to different parts on the drive train? Checking your carrier bearing sounds like a good starting place along with investigating the leaky seal. Sounds have a funny way of traveling through metal.

 

i'm not familiar with the long rod technique, but would love to hear more. it was a bit unnerving to have it in gear, on jacks and walking around it. i'd love to get under it to investigate, but i keep thinking of how i would explain, if i survived.

 

i checked the carrier bearing for play, and the only movement i could see was in the rubber cushion.

 

Thanks for all the input. After considering the comments, i jacked up the truck and spun the front tires with my foot. the right front turned slow and had a slight sound. i changed both hub/bearing assemblies and the noise went away. the first one took 45 minutes and the second took 30, including removing the spacers from each side. Not bad for a 64 year old lawyer with no power tools. i did add a harbor freight 24" breaker bar to my tool box to make removing and replacing lug nuts easier.