I have a 2000 rx 300 awd with 117K on it, works wonderfully...
This winter it has stayed outside..at night the temperature is about 4 F...I let the car warm up 2 minutes before I drive it. It doesnt have issues except for sometimes not wanting to get out of first or second even at 40 mph for the first 5 minutes of driving it if that long..when its warmer outside i have zero issue.

Anyway..my question...the awd system should be 4 wheels all getting power at the same time..when it detects slippage the rear wheels get up to 50% power and front 50%
this is my understanding..

and it usually works VERY well for me on snow and ice and mud and such.

The other day I started the car up half on pavement with snow and the rear half of the car on a downward incline. 4F outside..gave it 2 minutes...hit the Snow button and went into drive and slowly hit the gas..the car didn't move but the front wheels spun, so I figured i would try again and again...same issue...I pop open my door and give it a little gas..both fronts spin...I give it more gas and I can see the wheels spin so fast I can smell rubber on ice?...and the rear wheels don't move at all..not even spin or lurch..nothing. Usually when Im on a surface like water or mud I lose traction on front and back and I can see both front and back wheels spin even if the car doesn't move stuck in whatever

that seems wrong that my rear wheels seem to have zero power even when I almost floor it.

am I missing something? I ended up going in reverse and driving through my entire backyard to get back on top pavement on avoiding any hills onto the concrete.

The rear wheels didnt seem to engage or move at all on a day with 4F weather on ice with a 2 minute warm up

I took my car home 50 minutes later warmed up fully and put it in the same situation with the front wheels higher than the rear and tried to get out of it while having the door open to look at the wheels in the back. they spun perfectly like usual and the car moves forward without issue.

Is this a weather issue?
or a warm up issue?
or what

I know most people dont leave their rx's in 4F weather outside but I do.

when its warm out I never had this issue

Someone teach me what happened or share whats the issue, does the rear diff need to warm up before it works?

my AWD in the summer and warmed up winter saves my @$$ alot and like I said, once its warmed up It works great all 4 wheels

 

Dumb question, but are you sure you have AWD?

Secondly, the AWD system in the RX is not all-symmetrical like the Subaru system that goes from "the wheels that slip to the wheels that grip." It's 50/50 to back/rear all the time and I think it sends power unfortunately to the wheels that slip to try to get grip.

Really, I can't imagine if AWD how it would have sent all the power up front and then rears did nothing for traction.

Also, "SNOW" mode just makes the transmission launch from 2nd gear, instead of 1st, so you're not putting that much torque to the wheels and try to get more grip. Doesn't really "help" per say for any sort of power distribution of front or back.

As for the slow shifting when cold, that's just the way that the RX was designed. Until the engine hits about the 3rd hashmark, the transmission is retarded (sorry Sarah Paline) from shifting to 4th gear and stays in 3rd to speed up the warming process. If you're really not leaving 1st or 2nd gear, then you might have tranny issues.