GMC Yukon XL Denali Owner's Manual page 403

Two-Wheel-Drive Vehicles
Dinghy Towing
Notice: If a two-wheel-drive
vehicle is towed with all four
wheels on the ground, the
transmission could be damaged.
The repairs would not be covered
by the vehicle warranty. Do not
tow a two-wheel-drive vehicle
with all four wheels on the
ground.
Two-wheel-drive vehicles should not
be towed with all four wheels on the
ground. Two-wheel-drive
transmissions have no provisions
for internal lubrication while being
towed.
To dolly tow a two wheel drive
vehicle, the vehicle must be towed
with the rear wheels on the dolly.
See Dolly Towing (Rear Wheels Off
the Ground) following.
Vehicle Care
Dolly Towing (Front Wheels Off
the Ground)
Notice: If a two-wheel drive
vehicle is towed with the rear
wheels on the ground, the
transmission could be damaged.
The repairs would not be covered
by the vehicle warranty. Never
tow the vehicle with the rear
wheels on the ground.
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