Last post on Sep 21, 2007 at 11:05 AM
You are in the Toyota Sienna
What is this discussion about?
Toyota Sienna, Van
Jun 02, 2007 (11:58 pm)
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.
#16 of 34 Re: AWD type? [siennasweden]
Jun 03, 2007 (3:59 pm)
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.
#17 of 34 Re: AWD type? [ateixeira]
Jun 04, 2007 (8:05 am)
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.
Jun 04, 2007 (10:31 am)
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.
#20 of 34 Re: non AWD driving in Snow [lazzar]
Jun 06, 2007 (7:29 am)
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.
#21 of 34 Re: non AWD driving in Snow [loucapri]
Jun 06, 2007 (8:00 am)
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).
#22 of 34 Re: non AWD driving in Snow [loucapri]
Jun 06, 2007 (8:14 am)
Apples and Oranges....
Our 2000 AWD T&C has a VC, viscous coupling, to the rear driveline that is ALWAYS in effect at a reasonably high level, additionally the fluid is obviously formulated to have a very high "attack" rate, rapidly increasing torque coupling coefficient, upon front wheelspin.
Whereas the Sienna has a simple open center diff'l and relies on TC braking (and engine dethrottling) to apportion engine torque to the rear driveline ONLY AFTER front wheelspin/slip occurs.
#24 of 34 Re: AWD real experience [loucapri]
Sep 11, 2007 (7:10 am)
Our 2005 SLE AWD has 45,000 problem-free miles if you discount the run-flats that Toyota replaced at 24,000 miles under the revised bumper-to-bumper warranty. We live on top of a ridge in mountainous WNC, and AWD is more of a precaution than a regularly-needed feature, because our snow is rarely more than 6 inches at a time and it melts quickly...but it is a real issue when your are climbing a winding, 14 % grade to get home.
I have never spun a tire in the snow or slush or off road when camping. The ride is a little too low to attempt serious off-roading in a Sienna, but its the most reliable people and luggage hauler on the market that isn't a giant SUV. We have made trips to SC beaches, the Gulf Coast of Florida , Louisiana and Michigan, and the same car that enables our family to quietly and comfortably eat up interstate at at 75 mph (while my wife reads or works on the laptop via wireless data modem,my mother-in-law reads or sleeps, the 17 yo and the 11 yo watch DVD's or listen to whatever they want on headphones) also allows us to ride along with a great sense of safety and security in snow and heavy rains. The seats are so comfortable and supportive that I choose to drive the Sienna on my business trips to Eastern NC, etc.
My average over 45,000 is 18.9MPG, and we get around 22 MPG on long trips with 5 people and all the luggage, etc. That is the same as my other vehicle , a 2004 Subaru Forester XT, which requires premium fuel. The Subaru is a lot more fun to speed up, down and around mountain roads, but it was a crowded, packed situation going to the beach.