I have MT ATZ 245/70/17 on my vehicle, and at a jeep event on the weekend here in Australia I damaged the side wall and could not get a new tyre (this is not a common size over here). I had the option of getting an original 245/65/17 but someone said if you have different tyres on with QD II you will stuff the diffs in no time at all, so much so that you have to have similar tread wear on both sides. If it is that sensitive it would mean you have to buy 2 tyres if you damage one that is over half worn. Does anyone know if this correct?
From the Owner's Manual (note: QDII uses the QTII transfer case):
Quadra-Trac II Operating
Instructions/Precautions — If Equipped
The Quadra-Trac II transfer case is fully automatic in the
normal driving 4 HI mode. The Quadra-Trac II transfer
case provides three mode positions — four wheel drive
high range, neutral, and four wheel drive low range.
This transfer case is fully automatic in the 4 HI mode.
This transfer case divides engine torque almost evenly
with 48 percent of engine torque to the front axle and 52
percent of engine torque to the rear axle. When speed
differences are increased between the front and rear drive
shafts, the transfer case can transmit up to 100 percent of
available engine torque to the front or rear drive shafts.
When additional traction is required, the 4 LOW position
can be used to lock the front and rear driveshafts together
and force the front and rear wheels to rotate at the same
speed. The 4 LOW position is intended for loose, slippery
road surfaces only. Driving in the 4 LOW position on dry
hard surfaced roads may cause increased tire wear and
damage to driveline components.
When operating your vehicle in 4 LOW, the engine speed
is approximately three times that of the 4 HI position at a
given road speed. Take care not to overspeed the engine
and do not exceed 25 mph (40 km/h).
Proper operation of four wheel drive vehicles depends on
tires of equal size, type, and circumference on each
wheel. Any difference will adversely affect shifting and
cause damage to the transfer case.
Because four wheel drive provides improved traction,
there is a tendency to exceed safe turning and stopping
speeds. Do not go faster than road conditions permit.