AWD Lock Button

[jim_jim]

Hi All
I recently bought a 2007 Nissan Murano S AWD and time and only realized it now with snow approaching that it is not a full time AWD car.

After researching online i figured out that the lock button should be used only in snow conditions as there might be a dramatic diffrence in mpg?


I dont know whether the lock button in my Murano is functional or not?As i dont see any light on the button going on or off when i click on the switch and there is nothing displayed on the center panel indicating the AWD is on.


Is there any way to tell whether it is working as it should?

Thanks

[zebelkhan]

No need to engage AWD button unless you are stuck in snow and cannot move. Once going, it is recommended that you turn it off. It disengages automatically when it gets to about 6 mph anyways.

Remember that AWD system is computer controlled and will engage automatically at any speed when slip is detected, even when the button is off. So just leave it in off position and focus on driving. In fact, Nissan does not recommend engaging the button at all unless you are stuck because by manually putting it in AWD mode, you run the risk of driving the car on dry (without ice or snow) pavement which can damage the transfer case.

There should be a light on the dash that comes on when AWD is engaged.

[katz_n_jamer]

I have been advised by various members of this Forum to NEVER engage the AWD lock. Doing so will do irreparable damage to your transfer case and require over $4000 in repairs. For that reason I have put a piece of black tape over mine so I'm not tempted to use it.

Kind of makes one wonder why it's there in the first place!

[jim_jim]

Sorry for my ignorance guys.I just tried to turn it on and i see a indicator in the fuel meter.I will make sure i wont engage it will automatically engage when it detects the front tires slipping

[Carguy75]

The AWD lock will unlock after 15-20mph automatically. However, you should only use the AWD lock button to get better low speed traction in slippery situations like on icy roads. When you press the button the Murano will grip strongly to the road and you will hear the system work as you drive.

[Pilgrim]

Originally Posted by katz_n_jamer

I have been advised by various members of this Forum to NEVER engage the AWD lock. Doing so will do irreparable damage to your transfer case and require over $4000 in repairs. For that reason I have put a piece of black tape over mine so I'm not tempted to use it.

Kind of makes one wonder why it's there in the first place!

Let me re-interpret, because there is some inaccuracy in the comments above.

There is no "absolute" about the lock button as stated above. Actual human judgment is called for.

As noted earlier in this thread, it is OK to use the lock as intended - which is only when you are stuck while parked in an extremely low traction situation, or otherwise need a little more traction to get moving from a stop.

At that point, the lock should be engaged only long enough to get moving, then turn it off.

It is not accurate to say "Doing so will do irreparable damage to your transfer case and require over $4000 in repairs." Not true.

Using the lock INAPPROPRIATELY and especially on dry pavement while turning and going around corners can (not "will," but "can") possibly cause damage to the transfer case by putting undue loads on it when front and rear wheels turn at different rates, which creates loads on the transfer case, which in turn may - not will - cause damage.

If you don't use the lock on dry pavement and don't accelerate hard or try other extreme measures to get out while stuck, you should be OK.

This vehicle is All-Wheel-Drive, NOT Four-Wheel-Drive. AWD in this case means it's a passenger car chassis (Nissan Altima) with a mid-size SUV body mounted on it. The transfer case is not designed for heavy loads, extreme stress, or off-roading; it is only designed to provide traction for the driver on slippery surfaces. Evidence of this is that the lock kicks off at (I believe) 16 MPH, so its only function is to get you moving.

A 4WD vehicle is generally truck-based and is designed for heavy loads on the transfer case, extreme differences in traction over a prolonged period, and such activities as off-roading and climbing over obstacles. The drivetrain is much heavier-duty and able to withstand extreme service. Most 4WD systems can be engaged at any speed, including highway driving. Generally speaking, they are strong enough that if you start turning corners on dry road in 4WD, you will wear out the tires before bothering the transfer case.

[Halwg]

I think in the 2012's at least that AWD lock disengages around 6 mph to keep from damaging the transfer case. It's doubtful under normal driving conditions that one would ever have to use it.

[Pilgrim]

Originally Posted by Halwg

I think in the 2012's at least that AWD lock disengages around 6 mph to keep from damaging the transfer case. It's doubtful under normal driving conditions that one would ever have to use it.

I think you're right - I have seen that number quoted before. The earlier series went a few MPH more before disengaging, IIRC.

[katz_n_jamer]

Well, I stand corrected!

[Eric L.]

I believe from 2005+, the AWD was reprogrammed to disengage at 6mph vs 18mph in earlier models. Some people have had problems with the actual button - it used to be a rocker switch but was changed to a toggle switch (at the same time adjusting the cutoff from 18mph to 6mph). For 2003-2004 owners, if the rocker switch malfunctioned (or fell into the actual console), they replaced it with the toggle switch (and the lower cutoff).

[Carguy75]

I believe that the AWD's failsafe will prevent any problems to the transfer case, if anything you will loss some MPG's if you use it every time you stop the Murano due to the increased traction until 6-18 mph or so ,in which the AWD lock cuts off. P.S my 06 Murano owners manual stated the AWD lock goes back to the normal auto mode after 6 mph.

[Pilgrim]

Originally Posted by katz_n_jamer

Well, I stand corrected!

No insult intended - just wanted to provide a more nuanced explanation of what goes on with that system.

[njjoe]

The big shortcoming with the MO's AWD system is not the transfer case itself, but the lack of a center differential to protect the transfer case.

The vast majority of AWD systems employ either a center differential or viscous coupling between the front and rear axles. Both systems enable the front and rear wheels to operate at different speeds (as when the vehicle is turning) to prevent the drivetrain from binding.

The MO has neither a center differential nor a viscous coupling. When the AWD LOCK button is engaged it solidly locks the front axle to the rear axle. Because the rear wheels turn slower than the front wheels when the vehicle is turning the difference in axle speeds causes the drveline to bind. The sharper and longer the turn, the greater the binding.

If the AWD LOCK button is engaged and the vehicle is traveling below the disengagement threshold and the MO is driven in a continuous right or left turn on a high-traction surface the difference in front and rear axle speeds will cause the drivetrain to bind. If the opposing torque on the transfer case exceeds its design limit it can fail catastrophically.

The addition of either a center differential or viscous coupling could have given the MO full-time AWD capability, but the trade off would have been increase costs and reduce fuel efficiency. Those trade-offs were not desirable for this particular vehicle.

-njjoe

[njjoe]

Originally Posted by Carguy75

I believe that the AWD's failsafe will prevent any problems to the transfer case, if anything you will loss some MPG's if you use it every time you stop the Murano due to the increased traction until 6-18 mph or so ,in which the AWD lock cuts off. P.S my 06 Murano owners manual stated the AWD lock goes back to the normal auto mode after 6 mph.

Not true. The "failsafe" is speed-related, not torque-related.

If you engage the AWD LOCK on dry ground and drive a continuous right (or left) turn at 5 MPH no "fail safe" will intervene and you risk damaging a drive line component.

-njjoe

[katz_n_jamer]

Wow, this is way more complicated than I thought when I bought it. I actually thought the AWD lock would be a desirable feature. Now it just seems like a detriment.