How does the AWD system work? ('09 Vibe)

[sbzero]

***UPDATE: On the '09+ AWD Vibes, the AWD is full-time! I confirmed this by putting my Vibe up on a lift and putting it into gear. All four wheels spun in standard driving mode, with Trac Off, and with Trac Off/VCS Off. Good stuff! So, when I bought the car, the dealer told me that my '09 Vibe AWD operated as FWD until the "Trac Off" button was pressed, at which point it worked as AWD, until reaching about 35mph. I thought this was extremely lame, but he explained that it "turned on the AWD to get you out of mud or snow if you're stuck, then turned off the AWD once you get on the road and get up to speed."I've been driving this car for nearly 2 years on this assumption, being disappointed and slightly depressed about it.Today I had a little epiphany and read my owner's manual. According to the owner's manual, the AWD system is full-time, sending power to all four wheels all the time. The "Trac Off" button just temporarily disables the Stabilitrak until you reach 35mph.Does anyone have any more detailed info on this? I'm not keen on trusting car salesmen and I'm also not keen on trusting the owner's manual, since they list the incorrect transmission fluid. I've never put my car up on a lift and hit the gas to see which wheels turn, which I'm gonna do if I can't find out what the truth is!

[09vGT]

I'm pretty sure the salesman is full of crap. Someone can correct me if I'm wrong, BUT, even the AWD Vibe only operates as a FWD car until it detects slipping, which is when the AWD system kicks in. Turning off the traction and VSC does not do anything but, well, that. So, the AWD is automatic, and only comes on when it detects that its needed. Some cars call this "Smart AWD Systems. There should be a yellow illuminating light that will come one when the system is active. So, you are only pulling with the front two wheels until you need the rear wheels also.

[KITT222]

Quote, originally posted by 09vGT »I'm pretty sure the salesman is full of crap. Someone can correct me if I'm wrong, BUT, even the AWD Vibe only operates as a FWD car until it detects slipping, which is when the AWD system kicks in. Turning off the traction and VSC does not do anything but, well, that. So, the AWD is automatic, and only comes on when it detects that its needed. Some cars call this "Smart AWD Systems. There should be a yellow illuminating light that will come one when the system is active. So, you are only pulling with the front two wheels until you need the rear wheels also. That's at least how the 03-08 Vibes are, as claimed by their drivers and the manual.If you're miffed about the manual saying the wrong fluid, its just because GM wants their fluids in it.

[sbzero]

Well, they actually list the tranny fluid as T-IV, which is a Toyota product, and the correct fluid for '03-'08. The actual fluid on all the '09+ is T-WS.

[KITT222]

... weird. Well I haven't really studied the underside of my mates 03 AWD, but there might be a way you could set up a camera to catch if the driveshaft engages, and at what speeds it does. I found this. Its about the Lexus RX, but the active torque control is also on the latest Matrix.http://www.lexus.com/models/RX....html

[joatmon]

the 03-08 models worked by using a "viscous coupling"The rear drive sharft turns all the time the car is moving. There is a can on the front of the rear differential called a viscous coupling, it is full of some fluid and two sets of impeller blades. One set of impellers is connected to the driveshaft, the other is connected to the differential.When all is fine, all four wheels are spinning about the same speed, there is no rpm difference between the drive shaft and the differential impeller blades. When one of the front wheels slips, the driveshaft impellers spin faster than the differential impellers, and the driveshaft impellers push fluid against the differential impellers, transfering torque and driving the rear differential.It's always there, completely automatic, no sensors, switches, anything active. Whenever there is a speed difference between the two sides of the coupling, torque gets transferred from the faster to the slower side.I have no idea if the 09-10 AWD vibes use the same system or not.

[star_deceiver]

Pressing the "trac off" button merely turns off the traction control. Nothing more, and it will reactivate once you reach 35mph. Hold the "Trac off" button for 5 seconds when you're at a dead stop and you will turn off the traction control and vehicle stability control "VSC" until you either turn off the engine or press the "Trac off" button again.Quote, originally posted by joatmon »I have no idea if the 09-10 AWD vibes use the same system or not.It is the same. The fluid is extremely thick and when slip is detected the fluid literally acts as a solid. Quote, originally posted by sbzero »I've never put my car up on a lift and hit the gas to see which wheels turn, which I'm gonna do if I can't find out what the truth is! The stability/traction control system doesn't like this... you're going to hear a lot of beeping if you don't turn those systems off before you do this.

[sbzero]

"A LOCK switch can be used to manually select a 50:50 torque split for enhanced low-speed traction in conditions like mud or snow. Once the RX reaches 25 mph, the LOCK switch automatically disengages."That's the quote on the Lexus system from the link you provided...I work at a lube shop, and from what I've seen on the RX350 AWD's that come in, it appears to be the same setup as the Vibe/Matrix AWD set up. Same fluids, same diff/tcase. Vibes/Matrixes don't have a LOCK switch, though, which is what it sounds like the salesman was trying to say to me.

[sbzero]

[sbzero]

^^^The Owner's Manual info listed above is 100% accurate. I put my Vibe up on a lift today and put it into gear to see which wheels spin. All four spun in all three driving modes (standard, trac off, trac off/vcs off).

[KITT222]

Cool. By the sounds of it though, the Lexus has a coupler lock type thing in it, to lock the two impellers together. Kinda like torque converter lock up.