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.