I'm an electrical engineer (mechanically inept) so I've got to know how things work so my feeble mind can attempt to calculate all possible outcomes of situations that will never happen. I naturally drive AWD vehicles, one of which is a 2000 RX300 AWD. Had it about 3 months, best vehicle I've ever driven. ANYWAY, I also have a 2002 Subaru Forester (was the best vehicle I had ever driven). Somewhere I once read the Subaru is full time AWD, with 90% front drive and 10% rear drive all the time. When the front wheels slip, the power split will go up to 50-50 until traction is regained.

My question: is the RX300 AWD primarily a FWD or RWD vehicle? Is power being applied to both front and rear axles continuously, or is it a situation where the non-powered axle is "kicked in" when the powered axle slips? In my "experiments" in 6-8" of snow recently in Michigan's upper peninsula, I can of course get the rear of the RX to slide out if I drive like an idiot. The Subaru will do this as well, although to a lesser degree. This "hard acceleration slide out" in 6-8" of snow therefore doesn't really tell me how this beauty is working.

Thanks in advance for any tidbits of knowledge.

Ryan

 

Trac or not?

Lexus for a while was offering AWD without traction control. Competitor, knowing this, jury rigged a set up with no traction on one side [front and rear] and RX failed miserably {FWD with trac had no-problem}. So how the vehicle behaves when you have slippage can be very different.

Salim

 

http://auto.howstuffworks.com/four-wheel-drive.htm

 

Salim - did not know this. My RX has no traction control.

Ryan

 

Don't loose heart. One side [both left or right] loosing traction, is possible but not very commen. Knowing the capability/limitation of the vehicle will keep the driver and passengers out of the jam.


Salim

 

Drove home in about 8 inches of snow last night, AWD worked like a charm! No slips or spinouts at all in "snow" mode on my 99 rx

 

The RX300 AWD is full-time AWD with even 50-50 front-rear torque split. Therefore it is possible to "wag the tail" in snow if you step on gas during a turn. The rear tires push it to a different direction than the front tires. Be aware of this effect and wait until you finish the tight turn before applying gas. You'll do fine.

Also note that AWD does not brake or handle any better than FWD. Some drivers either don't know or ignore this. Therefore most Colorado vehicles in the ditches are 4x4 SUVs.

 

Four wheel models do not have traction control, only two wheel drive does in 2000. The four wheel version options for a "Torsen" sure-grip posi in the rear. Mine has one, though I hardly use it on dry warm pavement. I've tested it in the dirt. The four wheel models additionally have a silicon packed "clutch " to prevent drive shaft wrap up in hard turns. It is just behind the transfer case on the propeller shafts. (what we in the US call driveshafts).

 

Oh, I learned something new today. I thought the RX was FWD 100% until slippage where it would transfer 50% to the rear wheels.

Ours is a 2000 as well and it starts up in snow without a problem. In turns, like the others have said, it can "wag" the tail if you apply too much gas. (But at that point you are probably applying WAY too much gas --- compared to if you were driving a FWD or RWD)

 

In '99 Traction control was available as an option on a FWD. Overtime it may have become standard on a FWD starting 2000.

Salim

 

50/50 split... good to know. Yeah, it's true, people drive 4x4s like they're invincible. I drive my AWD vehicles like a normal vehicle. I'm a huge AWD fan after two near death experiences in FWD cars... driving along and all of a sudden you're sideways at 50 mph with a logging truck coming at you. AWD won't prevent that completely, but it will reduce the chances.

A note on tires... I replaced the Integrities with Yoko G051s. I'll probably get the road noise with wear as others have commented on, but it's night and day over the Integrities so far.

 

All RX 300 and 330s have a 50:50 split AWD system.MY 1999 & 2000 had a viscous center differential and an optional limited slip rear differential. These were mechanical systems and you could be left with no drive under certain conditions. From MY2001 RXs have had an open center and rear differentials .Slip is handled by the Traction control system appropriating the torque front and rear and side to side to the end with the more traction. This system will give you drive with only one wheel having traction.

My 99 AWD had a limited slip rear differential and it was sure footed in the snow. I could drift it at pretty aggressive angles at high speeds and I always felt in complete control.We've had the RX330 for two years and haven't had a chance to try it in the snow yet. I suspect the VSC won't let me do those juvenile slides and will cut the fun early,not that I'm complaining.In an emergency situation I would rather have all the electronic help that's available.
Wonder if the VDIM hack for the IS and GS would work on our RXs VSC.