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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
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Experience:  30+ Yrs of auto experience, Award Winning Svc. Manager; Just Answer Customer's Choice Award Winner
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I have a 2009 Rav 4 AWD with whiring sound in rear end when

Customer Question

I have a 2009 Rav 4 AWD with whiring sound in rear end when traveling . A mechanic diagnosed it as a failed electromagnetic visious coupling which is expensive to replace. A question ...I have read that a coupling can be removed and the vehicle would then be just FWD. This advise online was with a 2007 Rav I believe that did not have this electromagnetic coupling
Submitted: 2 years ago.
Category: Toyota
Expert:  Toyota Service replied 2 years ago.
Hello. Welcome to Just Answer. Please allow me to assist you
The 2009 RAV/4 does use an electromagnetic coupling inside the rear differential. This is, if the diagnosis is correct, a very, very rare failure. In our shop (Toyota dealer service dept), we have never had an issue with the EM couplings as long as they have been fitted.
I would seek a second opinion on the original diagnosis.
With regard to disconnecting it, No. You do Not want to do this. If you encounter a situation where the transfer unit sends power to the rear driveshaft, you could damage the internals of the transfer case by creating an over-rev condition. This can and will destroy the transfer unit
If the EM coupling is indeed bad (again, extremely rare), you need to replace it. A much more common failure item on the rear axle is the rear wheel bearing/hub assemblies. I would think, based on vehicles that have come thru the shop that you probably have a wheel hub noise, not an EM coupling noise.
The recommendation here is to get a second opinion form a qualified Toyota tech, one who is familiar with this particular rear axle unit.
If you have any questions, please feel free to reply
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