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.
The bearing for the viscous coupler has gone bad. it whines loudly when in motion, and the volume correlates with the speed. according to feedback from online this issue happens a lot. toyota will not change the bearing ($50 plus labor). they will only change the whole coupler ($1800 plus labor) as they state the coupler is not serviceable. multiple people have serviced the working coupler to change just the bearing. toyota released a similar tsb for the rav 4 where the coupler failed.
Front axle leaking fluid
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.
When coming to a stop going about 5 mph towards a stop sign, my van accelerated into traffic. because the van jolted me into oncoming traffic, it almost caused an accident. it doesn't seem to matter whether i am braking or coasting, the van will accelerate uncontrollably.i have two children and not only am i putting their lives at risk, but mine also. i am not able to drive this vehicle due to how dangerous it is.
Rear differential coupler dysfunctional without no reason. all of the sienna especially awd are suffering from this issue.toyota denies to cover it.
While parked, driver began exiting vehicle and van began to roll and continued to roll when gear shift lever confirmed in park and brake continually pressed, eventually hitting a house.
All underwood components are not only vulnerable, but attractive to rodents. while parked overnight on 4 consecutive nights, rodents have chewed through wires despite attractive rodent poison in the engine bay, the poison is untouched and the wires are attacked every night. to date injector wires, sensor sires, fuel pump wires have been compromised, including sensors for the stability control system, which is disabled. i repaired damage by running new wires, clearing nests and set traps and poison, but now the the fuel system has been attacked and the fuel pump does not activate. 3 other cars parked in the same location for the past 5 months are untouched. safety systems are likely to be compromised for any person who must park these outdoors.
Joining highway in a situation where vehicles giving way cause hesitation and then give way causing braking then acceleration repeatedly, transmission refused to downshift on kick down, vehicle would not accelerate, actually slowed significantly forcing following vehicles to brake .vehicle eventually began to pick up speed.generally poor response from transmission in all modes. transmission drops out of drive at low speeds causing engine to race before taking up drive, very hard to operate vehicle smoothly.. excessive engine vibration and noise for this price point ,known more refined diesels knocking from steering column on constant radius turns when making small steering corrections, detectable at low and moderate to high speed. *tr