Hello,
If you are hearing a whining or howling sound from the back of your LE or XLE AWD Sienna, it may be a failing bearing in the electromagnetic (sometimes called viscous) coupler. This problem tends to come on gradually and it can be both annoying and worrying. The issue with the failure is less the diagnosis of the problem and more that Toyota is ripping off owners when they trying to get the problem fixed.
The issue is that Toyota want you to replace the whole coupler "Electro Magnetic Coupling Sub-Assembly part #41303-28013" that costs $500 to $1800 depending on the parts source. However to fix this problem you don't need a new coupler, you need a simple bearing replaced. The replacement bearing is NSK Japan 95DSF01 A1CG3 Differential Bearing for Toyota 90363-95007 95x120x17 mm. There are two part numbers for this bearing: 90363-95007 and the older 90363-95003. Afaik either will work. This electromagnetic coupler has been around quite a long time in Toyota's lineup, and the bearing appears in parts drawings for cars from the 90s. I searched and could not find the exact parts drawing that shows the internals of the coupling for the 3rd gen Sienna, and if you search for this bearing number for 3rd gen Siennas Toyota's databases they will tell you the bearing doesn't fit. Toyota parts databases say the bearing is for 2003-2007 models. There are a number of drawings online with the coupler assembly. I have attached one below. You can order this bearing from Toyota, however my experience was that if you tell the parts desk that your have a failing bearing in the electromagnetic coupler they will push you hard on replacing the whole unit for $1500-$2500. I actually had to hang up and call the parts desk on another day to order the bearing using part # 90363-95007 for $90 CAD, and picked it up when it arrived at the dealer. There are cheaper prices online, I just wanted the ability to return it if it did not fit.
Getting the bearing replaced.
After having two independent shops tell me they wouldn't replace the bearing because Toyota says replace the unit, and the shops would rather they charge me their 20% markup on a $1800 part, I went to a transmission shop. The transmission shop said no problem, they are used to repairing transmissions and differentials that many auto manufacturers will not fix and say to replace the whole unit. In short they are problem solvers used to ignoring the advice from a manufacturer's parts department.
It took the trans shop a few hours of labor and they charged $470. So final cost for the repair was $560 CAD. Far less than the $2300-2500 the toyota dealer wanted for the same repair. I hope that helps someone, it tooks quite a bit of research to find the information that Toyota has strived to hide from owners and repair techs over the years.
cheers,
Robin.
If you are hearing a whining or howling sound from the back of your LE or XLE AWD Sienna, it may be a failing bearing in the electromagnetic (sometimes called viscous) coupler. This problem tends to come on gradually and it can be both annoying and worrying. The issue with the failure is less the diagnosis of the problem and more that Toyota is ripping off owners when they trying to get the problem fixed.
The issue is that Toyota want you to replace the whole coupler "Electro Magnetic Coupling Sub-Assembly part #41303-28013" that costs $500 to $1800 depending on the parts source. However to fix this problem you don't need a new coupler, you need a simple bearing replaced. The replacement bearing is NSK Japan 95DSF01 A1CG3 Differential Bearing for Toyota 90363-95007 95x120x17 mm. There are two part numbers for this bearing: 90363-95007 and the older 90363-95003. Afaik either will work. This electromagnetic coupler has been around quite a long time in Toyota's lineup, and the bearing appears in parts drawings for cars from the 90s. I searched and could not find the exact parts drawing that shows the internals of the coupling for the 3rd gen Sienna, and if you search for this bearing number for 3rd gen Siennas Toyota's databases they will tell you the bearing doesn't fit. Toyota parts databases say the bearing is for 2003-2007 models. There are a number of drawings online with the coupler assembly. I have attached one below. You can order this bearing from Toyota, however my experience was that if you tell the parts desk that your have a failing bearing in the electromagnetic coupler they will push you hard on replacing the whole unit for $1500-$2500. I actually had to hang up and call the parts desk on another day to order the bearing using part # 90363-95007 for $90 CAD, and picked it up when it arrived at the dealer. There are cheaper prices online, I just wanted the ability to return it if it did not fit.
Getting the bearing replaced.
After having two independent shops tell me they wouldn't replace the bearing because Toyota says replace the unit, and the shops would rather they charge me their 20% markup on a $1800 part, I went to a transmission shop. The transmission shop said no problem, they are used to repairing transmissions and differentials that many auto manufacturers will not fix and say to replace the whole unit. In short they are problem solvers used to ignoring the advice from a manufacturer's parts department.
It took the trans shop a few hours of labor and they charged $470. So final cost for the repair was $560 CAD. Far less than the $2300-2500 the toyota dealer wanted for the same repair. I hope that helps someone, it tooks quite a bit of research to find the information that Toyota has strived to hide from owners and repair techs over the years.
cheers,
Robin.