Two Wheel Rx300's In The Snow

[LexKid630]

How do the two wheel drive rx300's handle in the snow? How much of a diffrence from AWD?

[dal]

How do the two wheel drive rx300's handle in the snow? How much of a diffrence from AWD?

←

I can't offer a comparison, but I can report that my 2WD does OK in the snow - albeit DC snow, so not as healthy or frequent as northern parts. But on the few 4-8 inch and an occasional 12+ snow, I was out and about before much plowing had been done (i.e. in the first 3-5 days around here!). Didn't try to burst through any 10 foot drifts or scale any glare ice inclines. I think knowing how to drive in snow (WI training) plays a big part in vehicle performance in snow. I have Michelin Cross Terrains the last 65k of 105k total miles (on second set) - they give enough bite in packing snow.

That said, I'm certain the AWD provides mechanical advantage.

Cheers.

[LexKid630]

I've had 3 RX300's with the AWD. My 99 and old 2003 were great in the snow. Went uphill like it was nothing in snow. I've never driven a front wheel drive rx300 OR rx330 in the snow.

[wwest]

The RX300's version of AWD isn't.

The engine torque in the AWD version of the RX300 is heavily biased to the front, 90/10 F/R, and over an extended perior of front wheel slippage the viscous coupling will "tighten" up and change the ratio to as much as 75/25 F/R. This statement and numbers were confirmed on a four wheel dynamometer.

So a FWD RX300 equipped with VSC/Trac etc, is likely just as good in the snow as any AWD RX300. The AWD RX330 is even worse.

[LexKid630]

The RX300's version of AWD isn't.

The engine torque in the AWD version of the RX300 is heavily biased to the front, 90/10 F/R, and over an extended perior of front wheel slippage the viscous coupling will "tighten" up and change the ratio to as much as 75/25 F/R. This statement and numbers were confirmed on a four wheel dynamometer.

So a FWD RX300 equipped with VSC/Trac etc, is likely just as good in the snow as any AWD RX300. The AWD RX330 is even worse.

←

I didnt know that! Then who in their right mind would ever buy an AWD? i mean if they knew this information.

[katzjamr]

Maybe they like the added excitement of transmission roulette

[RX in NC]

Touche! I'd laugh at that comment if it didn't hurt so much....

[monarch]

Here in California, when the Highway Dept. has chain requirements during the winter,

a two wheel drive vehicle with dedicated snow tires is exempt from chain requirement. So are 4WD and AWD vehicles without snow tires installed. So in many cases it appears a 2WD vehicle with dedicated snow tires is approximately as capable in the snow as an AWD vehicle fitted with conventional all season tires.

Snow in California? Yes, in the high Sierra Nevada mountains - enough even to bury a motorhome http://i5.photobucket.com/albums/y189/mastertech/echoaa.jpg

[nitro]

Wow. I had no idea the bias was so unbalanced. I guess I wasted my money buying the AWD version.

[LexKid630]

Wow.  I had no idea the bias was so unbalanced.  I guess I wasted my money buying the AWD version.

←

The Front wheel drive transmissions on the rx's must be different than the FWD's on the Toyota Camry. I had an 04 loaner Camry and it was horrible in the snow.

I can't believe the difference b/t AWD and FWD on the rx's is that small. Is it that the AWD systems suck, or that the FWD systems are EXCELLENT?? If they're about the same, what's the difference LOL Why even make an AWD?

[wwest]

"Why even make an AWD?"

Does the statement "One born every minute" suffice?

[SeaDuck79]

"Why even make an AWD?"

Does the statement "One born every minute" suffice?

←

Didn't have much choice. Our dealer (Lexus of Bellevue) said that all of the 330s shipped to the NorthWest were all AWD. Certainly all I saw on their lot were. I don't mind - makes the spousal unit feel better about driving in inclement weather.

[LexKid630]

Plus all the FWD rx300's were stripped. I couldn't find on with nav, heated seats AND a spoiler. They had nav, spoiler, but no heted seats..then they had nav w/ heated seats, but no spoiler.

Plus when i bought all my AWD rx's the people at the dealer told me i needed them for the snow. I wish i knew then!

[wwest]

"Why even make an AWD?"

Does the statement "One born every minute" suffice?

←

Didn't have much choice. Our dealer (Lexus of Bellevue) said that all of the 330s shipped to the NorthWest were all AWD. Certainly all I saw on their lot were. I don't mind - makes the spousal unit feel better about driving in inclement weather.

←

There are ways you can make an RX300 more truly an AWD vehicle, even rear torque biased. First, install ~1.5 wheel spacers all around so you can use snowchains at the rear first and then also at the front as required. The spacers also allowed me to upgrade to 17x8 wheels and use Bridgestone Turanza 235/65-17 summer tires.

I never hesitate to throw on at least one set of snowchains if the weather, and these NW drivers, dictate. So I run summer tires year 'round for quietness.

If you want a true AWD RX300 you can remove the transaxle mounted diff'l case, open the center diff'l case, remove most of the spider gearing and weld the rear drive spider gear into place. Now you will have a good solid mechanical coupling to the rear driveline and the existing viscous coupling for driving the front if the rears begin to slip severely.

Keep in mind that the RX300's viscous coupling fluid is not formulated for a serious level of torque coupling as some are (AWD Chrysler T&C immediately comes to mind), 25% to the front is the best you are likely to get and that only after some serious period of rear drive slippage.

Converting the RX330 to rear biased AWD is a bit more difficult but it appears that it can likely can be done by purchasing and installing the Viscous clutch assembly for an RX300.

[LexKid630]

So basically the AWD is a more complicated, problem filled FWD....that's nice to know LOL

[tealboy]

I am certainly far from any expert on the subject but I do use my 4x4 exped in awd every weekend and it really doesn't take much from the other wheels to keep me moving. The 4wd version is 4wd limited slip all the time, but i use the awd frequently, and you can hear and feel the other wheels chipping in when needed. Places that i would get stuck in 2wd, works just fine. Now, i realize this is no rx 300 awd, but my point is, the only way i could be convinced awd didn't make a difference is in a side by side comparision in the snow (or in my case, mud). Again, a small amt of help from another tire or two is the difference between stuck and not stuck.

[jgr7]

tealboy you are exactly right, any one who has FWD only can tell right away when you turn a corner in the rain and give it some gas. The front wheels will spin like crazy. With the AWD you get a very slight slip then the computer takes over and you just go around the corner with no more slipping. If you didn't have the AWD in the snow you would find your self spinning on those slight uphills that the little push from the back will stop. I've been driving FWD cars for over 22 years and had an AWD since 98 and I can tell the difference.

Jeff

[LexKid630]

On front wheel drive cars, the back wheels have no power at all, NEVER.

Didn't think if it like that...It's nice to know that they're there in case you do need them in slipepry situations.

so there is a difference LOL?

[wwest]

So basically the AWD is a more complicated, problem filled FWD....that's nice to know LOL

←

"Problem filled......"

No, I did not say that.

More complicated, yes, but problem filled?

Not to my knowledge.

[LexKid630]

So basically the AWD is a more complicated, problem filled FWD....that's nice to know LOL

←

"Problem filled......"

No, I did not say that.

More complicated, yes, but problem filled?

Not to my knowledge.

←

By problem filled i meant all the premature rx300 AWD failures. It does seem that the FWD's don't have as many problems. Less moving parts = less posibility to break.

[lexus411]

I ve driven AWD RX's for the last 6 years in the worse snow storms and never had any problems. Great cars

[wwest]

So basically the AWD is a more complicated, problem filled FWD....that's nice to know LOL

←

"Problem filled......"

No, I did not say that.

More complicated, yes, but problem filled?

Not to my knowledge.

←

By problem filled i meant all the premature rx300 AWD failures. It does seem that the FWD's don't have as many problems. Less moving parts = less posibility to break.

←

Is it really conclusive that the premature transaxle failures are unique to the AWD model?

I have always been of the mind that the premature failures or the result of the inadvertent upshifts during coastdown which leads to the need to quickly downshift if the gas pedal is depressed shortly after the upshift.

In later models Toyota alleviated the premature failure problems by delaying the onset of engine torque in these circumstances using an e-throttle.

Does anyone know for certain what part or component is failing prematurely on these transaxles?

Due to the level of debris in the sump pan and the burned odor of my ATF at only 40,000 miles I have assumed it is the frictional surfaces of the transaxle clutches that are wearing out more quickly than the designers expected.

[patt]

The Front wheel drive transmissions on the rx's must be different than the FWD's on the Toyota Camry. I had an 04 loaner Camry and it was horrible in the snow.

I can't believe the difference b/t AWD and FWD on the rx's is that small. Is it that the AWD systems suck, or that the FWD systems are EXCELLENT?? If they're about the same, what's the difference LOL Why even make an AWD?

←

Your experience with the loaner Camry could be partly due to the tires they equiped it with. We have had our 94 Camry up in the Sierra snow a few times (including one time when the snow was pretty light and we got the CHP guy to us go without chaining up). It was fine - not all wheel drive but definately not horrible. I've had it in mud too - not my first choice but it was someplace I needed to go and it was raining on this dirt road. It took gentle handling but did okay.

We haven't had our RX400 in the snow yet but it sure was great in the rain this spring. It is our first AWD car. I buy the argument that when the front wheels slip the ability to transfer some torque to the back will help even if it is a smaller amount than can be delivered to the front.

Of course a lot of the cars I've seen get into trouble in the Sierra do it on the downhill. FWD and AWD don't make much of a difference when you aren't needing to apply drive.

[wwest]

"Of course a lot of the cars I've seen get into trouble in the Sierra do it on the downhill. FWD and AWD don't make much of a difference when you aren't needing to apply drive."

Except for engine compression braking on a FWD vehicle going downhill. The equivalent of throwing an anchor from the front, bow, of a boat while underway.

Then throw snow chains on the front, driven wheels, of one of these vehicle and you have a recipe for disaster.

[ritchieg]

How do the two wheel drive rx300's handle in the snow? How much of a diffrence from AWD?

←

I have never driven the RX300 2wd but I do have an AWD. I have driven many 2wd cars in the snow in the Sierra mountains in Calif/Nevada and do know their limitations. I drove my RX300 AWD in Sierra snow three different times last winter and it handled great.

Regarding the Front/Rear ratio of power: the ratio really does not matter unless you are in competition snow racing. Most of us do not use a lot of power when starting or accelerating in the snow. My understanding of the AWD system is that the ratio of 90/10 is used unless a tire starts slipping, then the ratio will change to reduce power to the slipping wheel to the point when it will regain traction. That means if both front wheels start slipping, the ratio could change to put more power to the rear with a ratio of say 75/25.

In any case, I was very happy with the performance of the AWD. I did try to spin the wheels when starting from a stop but it would not do so. It just launched forward as if there was no snow. I also tried some slow turns with various power levels and found the car to be very "roadworthy."

Good luck this winter & let us know how your RX handles in the snow.

PS: my 2001 AWD has 46000 miles and never has had any transmission problems (knock on wood!).