Differential Unit problems of the 2012 Toyota Sienna

The contact owns a 2012 Toyota Sienna. The contact stated that the rear differential was making an abnormal whirling and grinding sound. There were no warning lights illuminated. The contact called the local dealer but the vehicle was not diagnosed or repaired. The manufacturer was notified of the failure and referred the contact to NHTSA. The approximate failure mileage was 79,000.

My 2012 Toyota Sienna recently began making a loud whining noise from the rear axle area. Upon inspection, we were informed that the differential unit was failing and needed to be replaced. This would cost us between $2,500-$3,000. After some research, I discovered that this is a common problem with the Sienna, likely caused by a design flaw. The same unit was used on the rav-4, and after similar problems surfaced it was recalled and fixed by Toyota. Given the danger posed by failure of this part to a family vehicle, and the known existence of the problem by Toyota, it seems obvious that it should be immediately recalled and fixed by the manufacturer.

Unit is producing a speed dependent whine from the rear differential consistent with a bearing failure in the viscous coupler. Issue first observed with approximately 98,000 miles on odometer. This appears to be a common component failure on many Toyota awd vehicles manufactured in the last 15-20 years, and the component in question may be under-engineered to perform as expected in normal driving conditions. Replacement part costs $1300+ from Toyota, not including installation.

Says my rear differential - viscous coupler- is bad and needs to be replaced at a cost oof at least $1,300 and that doesn't include installation. Happened just as car went over 100,000 miles and is covered in rav 4 bc had same problem but not 2012 Sienna nothing happened except it suddenly started not because of anything I did.

My 2012 Sienna awd xle has 103k miles and has a whirring noise coming from the rear differential area for a while now. The pitch and volume is proportional to speed and is louder as speed increases. My research tells me this is a common defect with the coupling bearings in front of the rear differential. It seems that rav4 owners got a recall for the same issue, but Sienna owners did not. Toyota has redesigned this part on later models to avoid the issue. Hope you can get this resolved. Thanks.

Rear differential has failed at only 60k miles. Well documented issue for awd Sienna models yet no recall issued. Safety concern for this family of five.

Rear differential coupler dysfunctional without no reason. All of the Sienna especially awd are suffering from this issue. Toyota denies to cover it.