Rear ended noise

My son’s 2018 Tacoma has a howl noise coming from the rear end. Checked the rear differential fluid level and found that it was at least 24 ounces low. Added synthetic 75W90 fluid to correct level but still have a slight noise. Is it feasible to think this noise will eventually go away or do we give the dealership another chance to say that the noise is normal?

 

https://www.tacomaworld.com/threads...oise-howling-when-feathering-throttle.442341/

 

Thanks for the reply. Lots of good information.

 

@Jcran2 Hino manufactured rear axles make a whine or a howl. All of them do this to some degree or another. Seems to have no effect on durability. Whether you can live with it or not is a different matter altogether. Read the link SpiderRC posted and search this forum for more information. Mine does it as well. I ignore it.

 

Yes, I have it to, right around cruising at 80-90km. Mechanic changed the oil in the differential, said original oil was very dark, he also put in an additive. It's still there, really disappointed in Toyota about this, truck is far too expensive to have a problem like this. And I wear hearing aids and I can still hear it, sad! One thing I hate in any vehicle is little rattles or noises!

 

24 ounces is significant !!

when pinion + ring start to rotate...................almost immedia tely the rear end oil climbs the ring gera

the pinion is lubed by oil thrown from the ring gear

the proper amount of lubed carried in the diff + axle tubes lube the outer axle bearings

under normal driving conditions i would say the outer axle bearing have been compromised

more than likely the carrier bearings + the axle bearings have been starved for oil