Strange CVT/AWD behavior in deep snow

9495 · Dec 29, 2008

I had an interesting experience this last couple days here in Pullman, WA, hoping someone can tell me why this happens and if it's a problem or by design.

Note that I have a 2005 AWD, but do NOT have VDC.

We had really deep snow here (2+ feet) and the plows haven't been able to keep up. Without deep snow, I've been incredibly impressed with the abilities of the Murano on the compact snow an ice. However, thanks to the fuel shield making the Murano have the ground clearance of a squirrel, I've managed to get temporarily stuck on the deep stuff, primarily due to snow building up under the car.

Anyway, when stuck, I noticed that if in D, S, or L, I could get all four wheels to spin, but even with the pedal to the floor they would only spin slowly (like traction control was limiting power, but remember I do NOT have VDC). With the pedal to the floor, RPMs were still only at about 3k, it did NOT try to redline which I thought was interesting.

When in REVERSE, I could NOT get any of the tires to spin. There was pressure on the wheels, meaning that when I started giving it some gas it would move a tiny bit then stop, so I could tell it was getting some power, but it never had enough to actually spin any of the wheels in reverse no matter how far I pushed the accelerator. Same thing with the RPMs, it seemed like it was limiting itself because it knew it couldn't do it and was trying to avoid spinning the wheels.

Any thoughts? Is this something that I should have checked out, or is this a "feature"?

njjoe · Dec 29, 2008

C-

You must have really been suspended by the packed snow under the MO because unless you have limited-slip differentials (you don't) it is virtually impossible to get all four wheels spinning if even one has decent traction.

When you said the tires were spinning slowly at 3,000 rpm, how slow was it? What did the speedometer register? Is it possible one tire was spinning fast enough to register 120 MPH and initiate the high-speed limiter? Just a thought...

-njjoe

Eric L. · Dec 29, 2008

Perhaps this was also some sort of "safe mode" kicking in to protect the CVT from overheating. A long shot but who knows. I do know that if you the MO is stuck, VDC is close to useless for getting the vehicle out. The wheels try to spin but the traction control kicks in and you don't go anywhere - thats what the VDC off button is for - spinning the wheels to get out of a jam.

However if you are high centered, then you are really stuck and will need a push or to dig your way out (thats what the snow shovel is for).

9495 · Dec 29, 2008

yeah, we had to dig out under the tires and the stupid fuel shield, and got my brothers to push while I rocked it enough to get going again.

As for the wheels spinning, in D, S, L all four wheels were spinning SLOWLY. Maybe 1 - 2 mph? You could watch the tread going around. All four wheels about the same speed, none of them going fast at all.

I would expecting something like this with traction control, but without it?

I can only come up with 2 ideas:
1) Something isn't working properly
2) There is still some kind of CVT protection when awd kicks in, even without VDC

njjoe · Dec 30, 2008

Corin-

That is very puzzling.

To the best of my knowledge there is nothing on the MO to prevent the wheels from spinning up to full speed when all four tires are off the ground. I would have thought you could have redlined the MO with the wheels off the ground.

Just when we all thought we fully understood the inner workings of the CVT and AWD system you go ahead and present us with this little tidbit. Thanx a lot.

-njjoe

Gonzo · Dec 30, 2008

Did you every get the tires to spin faster at any point?

I would think that if the CVT was in a safe mode there would be some indicatoin with the dash warning lights.

Perhaps you and the MO had almost stopped time hence the slow moving tires even though you were in the present.....

9495 · Dec 30, 2008

The wheels were definitely NOT off the ground, all four had the weight of the car on them, it just wasn't going to move forward or backward due to the large piles of snow. What I would expect would be all four wheels spinning out, polishing the snow where they sit into a nice block of ice, but instead they only turn slowly (or not at all in the case of reverse).

Once I got unstuck, it seemed to work fine, and I've been driving all over town since then (rain melted most of the snow) without any other issues. Never any dash lights (I was looking), and I haven't yet gotten stuck again to test it.

9495 · Dec 30, 2008

I think I'll have to try an experiment when I get back home to Seattle and put my MO up on jack stands, all 4 wheels off the ground completely, and see what happens in that case. Maybe find some [relatively safe] way to put some resistance on one of the front tires to simulate a tire slip.

I take it nobody has done something similar yet?

Eric L. · Dec 30, 2008

Its probably not a good idea to rev the engine and spin the wheels off the ground. I'd chalk up the odd behavior of the wheels to some torque limiting software that protects the CVT.

teonek · Dec 30, 2008

I tried that and rear engage after moment an there is no limits. I think that big part of car weight was on the properel shaft (snow was under and was blocking it). I don't have any other idea.

9495 · Jan 4, 2009

Well, after driving around in the deep snow and ice for several days, taking a trip up to Spokane and back (75 miles each way) and then back to Seattle (300 miles) without ANYTHING seeming to have problems, I'm convinced this is by design. Most likely, as someone mentioned, limiting torque to save the CVT.

All in all, I'm very impressed with how the MO handles compact snow and ice, particularly with my new Yoko YK520 tires. The ONLY trouble I had was when the snow was too deep and basically high-centered me due to the fuel shield snowplow (which was the problem I reported on this thread).

Oh, and I had a BLAST in a couple of parking lots! Spinning around, sliding sideways, etc. Even doing that, I was very pleased that I was always in control, it slid very predictably. Of course, at those times, I was wanting to have MORE fun than it would let me...

g1teg · Aug 19, 2009

How would I know if I have the VDC package? Mine is an 03 SE, and I dont think I have it, because the Slip light never comes on if I pull off a shoulder and spin a tire a little. It never lets me spin much...

as for this thread, I go canoeing a lot, and when I launch, there is a beach. Last time I took the canoe off, and went to park the car, so I gunned it! Slightly up hill, in deep beach sand, and I couldnt spin my tires. Same thing as the OP, the RPMs came up REALLY slowly... i moved nice, and never felt like I was stuck, but felt like I was pulling a tree stump out!

9495 · Aug 20, 2009

If you have the VDC package, you will have a little switch on the dash left of the steering wheel that says "VDC Off". If you don't have the switch, you don't have VDC.

Also, on the 03 through 07 (I think) in order to have the VDC package, you have to have the touring package. So that means you'd have to have leather seats and the whole works before you can add the VDC option. If you don't have leather, you don't have VDC (you can find numerous gripes that I've posted on this forum related to this, as I didn't want the touring package and therefore couldn't get VDC at all.)

rtking · Aug 21, 2009

Sorry, late reply and only a hypothesis.

Since the Murano has an open differential (both front and rear), the AWD needs to use the ABS motors to help direct traction to front and rear tires, as well as side to side. It's likely that, when you high centered yourself, the Murano's AWD system was applying the brakes to each of the wheels and managing your throttle (remember, we have throttle by wire) to fight for traction. I'm guessing that's why your wheels were turning slowly while high-centered.

njjoe · Aug 21, 2009

rtking said:
Since the Murano has an open differential (both front and rear), the AWD needs to use the ABS motors to help direct traction to front and rear tires, as well as side to side. It's likely that, when you high centered yourself, the Murano's AWD system was applying the brakes to each of the wheels and managing your throttle (remember, we have throttle by wire) to fight for traction. I'm guessing that's why your wheels were turning slowly while high-centered.

That makes perfect sense... if his MO has traction control, which it does not.

-njjoe

benakoun · May 21, 2010

High rev'ing CVT and sometimes knocks

Hello.. I have a 2006 Murano and never had issues until this past winter. Whenever I start and drive the car, the RPMs jump as high as 4,000 and this even when I drive it out of my indoor garage. However, if i swith to neutral and then back to srive, the RPMs go back to normal. As stated this has only started in the 4th year. Also, some days when I leave in the morning and do a U-turn after day - 2 or 3 minutes of driving, I hear a knock (car kicks) or jolts. this only happens once as stated above...

I have just received a letter from Nissan stating they are extending CVT coverage to 100,000 miles - I assume because they've been having problems with these CVTs..

Has anyone experienced the same ??? Thank you

Strange CVT/AWD behavior in deep snow

9495

njjoe

Eric L.

9495

njjoe

Gonzo

9495

9495

Eric L.

teonek

9495

g1teg

9495

rtking

njjoe

benakoun

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