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Toyota Sienna AWD Problems/Questions

loucapriloucapri Posts: 214
edited March 8 in Toyota
I notice my AWD sienna has a leak from the rear "gear box?"
it's kind of a clear fluid.
I used to own a AWD Town and country and I had the same problem. Not sure if it is common to AWD


  • I, too, had a 2002 T&C with AWD and a 2005 XLE Limited AWD Sienna. You should NEVER see a leak from the gear box so take it back to the dealership as you may have a bad seal or another problem that I would think you'd want fixed before the snow comes :)
  • loucapriloucapri Posts: 214
    I got it fixed under warranty. But it took me whole day to explain to them "the leak is in the rear" and they kept calling me and told me they didn't see any leak (becauae they kept looking at the oil pan near the engine)
  • loucapriloucapri Posts: 214
    I know the AWD gets less than the FWD but shouldn't be that much.
    We got a disappointed 16mpg in avg.
    I am not sure how my wife drives the van but I will consider "normal" driving with 70% freeway. Don't know why and what to do to improve the mpg. any idea?
    Maybe the run-flat tires?
  • loucapriloucapri Posts: 214
    Can anyone owns a AWD sienna shares there real experience with the van? I just want to see how they perform. Does the AWD sienna drives well on snow (that's prettly much the reason why we bought the AWD version, right?)

    Please share your opinion.
    FYI, I know AWD won't stop better so no need to talk about that part.
  • wheels13wheels13 Posts: 51
    After driving 40 miles in heavy slush the next morning I went to use the car it made a very loud sound from the drive shaft hitting the body. Drove anyway, kill or cure, and later found that the drive shaft in the center of the car was packed tight with frozen slush. Had to crawl under with a hammer to clear away the ice riding on the drive shaft. Have any other owners of this 2006 LE AWD seen this problem? The car has been around a few years? Thank you
  • loucapriloucapri Posts: 214
    was it cold outside when this happened?
    If you drove in heavy slush, sounds like the weather is not that cold.
    I remembered I couldn't steer my car when living in eastern washington many years ago but only happened under cold cold weahter because the ice built up around the front suspension.

    I don't think you need to worry about this because the worst case is the drive shaft got stuck and the lost of AWD for a while until everyting melt
  • mleonardomleonardo Posts: 45
    My AWD sienna handles very well in the snow. I run studded tires on seperate wheels in the winter and the van has never broken loose. It even handles well without studded tires. I have had a few problems however with the van in general. Number one is the tires! I HATE runflats. If you get a flat on the interstate, your stuck! Those tires will not hold up at 55 mph with no air pressure And you have no spare. I went around and around with Toyota about this and got nowhere. Another problem is the fuel mileage is HORRIBLE! My window sticker said 18mpg city and 24mpg hwy. That is an all out lie! I barley get 18mpg on the highway. This thing gets the fuel mileage of a V8 with nowhere near the power. My last complaint is the quality of the interior. Mine is falling apart. The leather cover on the driver's headrest is coming off. A panel on the driver's side of my dashboard keeps popping loose and the seat release on the rear seat keeps coming out of its mount. People make fun of domestics but I had fewer issues with a GMC that I sold to buy this van.
  • wwestwwest Posts: 10,706
    Your realization of poor FE is more the responsibility of the US Government than Toyota. Our government REQUIRES the manufacturers to test for FE under unrealistically favorable circumstances and then FORCES them to publish the results.
  • wwestwwest Posts: 10,706
    "..worse case is the drive shaft got stuck..."

    In that case the vehicle would be entirely NO GO.

    If the front wheels rotate but not the rear then the AWD tarction control system will apply the front brakes along with dethrottling the engine. If that doesn't work to "force" the rear driveshaft to turn you're dead in the (frozen) water.
  • mleonardomleonardo Posts: 45
    Yeah Im sure Toyota was sick with guilt being FORCED to publish numbers so favorable to their sales. I guess thats where they get their great reputation for fuel economy.
  • lazzarlazzar Posts: 1
    How good is the non AWD in terms of handling and getting stuck in the snow.

    We live in NH and not sure we can afford the AWD version.

  • ateixeiraateixeira Posts: 72,587
    Consider snow tires as an alternative, that might be a little cheaper. You do get traction and stability control.

    Still, I'd spring for a low mile CPO AWD model. Should cost no more than a new one, and the warranty is effectively longer in most cases.
  • Hi!
    Does anyone now what kind of differential thats in the 2007 awd?
    Electrical or something else?
    How fast does the awd comes on if a weel starts to spin?
    And how are the normally spread on the driveshaft 50-50% or 70-30% or something else.
    Thanks for any replays.
  • ateixeiraateixeira Posts: 72,587
    It's a full-time viscous coupling.

    Basically the power goes to both axles (50/50 by default IIRC), and when one rotates at a speed quicker than the other, they temporarily lock together.

    The fact that it's full-time means it's pro-active and should be very effective.

    Combine that with traction and stability control and if you get stuck, it's your own fault. ;)
  • wwestwwest Posts: 10,706
    The viscous coupling was dropped from the Toyota/Lexus (FWD)/AWD drive train across the board in '04 and while it was again adopted for the RX350 I haven't seen anything (I checked)for the other FWD/AWD products.

    Absent the VC you have a simple open differential with a slight overdrive ratio to the rear such that you get a little extra "kick" at the rear when TC activates and applies brkaing on the front, presumably slipping, wheels.

    That same overdrive ratio results in a normal F/R torque distribution of 95/5 absent TC intervention. And even with a VC it takes several seconds for the VC to stiffen up enough for a maximum of 75/25. Those numbers were obtained with my '01 AWD RX300 on a 4 wheel dyno so later VC formulations, say an RX350, may vary.

    In my judgement the FWD version with VSC/Trac will give just as good, maybe better, wintertime performance as would an AWD absent the VC. If the VC is again being used the fluid formulation has likely been changed for the better.
  • ateixeiraateixeira Posts: 72,587
    I don't think the Sienna changed, even though the RAV4 did, for instance.

    This article says it's still old 50/50 type system:
  • Ok thanks
    It seemes to be a rather old solution of awd.
    Volvo uses the Haldek much quicker system.
    Its a long time left to winter here in sweden ,but i will let you now what i think about it when it comes.
  • loucapriloucapri Posts: 214
    Prior to the LE AWD, we had a Town and Country AWD and it worked better than a Jeep (I am not kidding. A Jeep and a Ford Explorer tried to make the hill near my house and both failed but my T&C had no problem going that hill and I got to get home)

    The LE AWD works great on snow but I believe FWD works fine on light snow based on what other posted.

    If budget allows, get the AWD. We got our 04 used with 40K miles (we could have gotton a 06 12K mile FWD) but my wife and I decided to got the AWD since we don't have any 4WD or AWD at home.

    One caution about the AWD is the run flat tires. They are pricy and don't last that long.
  • ateixeiraateixeira Posts: 72,587
    You also can't get the 8 seat model. That's the reason I passed (we also have a Subaru in our fleet, so we have a snow car already).
This discussion has been closed.