GMC 2003 Sonoma Owner's Manual page 248

In rare cases when it's unavoidable and your vehicle
must be towed with two wheels on the ground, the
propeller shaft to axle yoke orientation should be marked
and the propeller shaft removed following the applicable
service manual removal/installation procedure. See
Service Publications Ordering Information on page 7-11 .
Dust or dirt can enter the back of the transmission
through the opening created by removing the propeller
shaft if proper protection is not provided. Also, check
the transmission fluid level before driving the vehicle.
Use the following steps to dolly tow your vehicle:
1. Put the front wheels on a dolly.
2. Put the vehicle in PARK (P).
3. Set the parking brake and then remove the key.
4. Disconnect the propshaft as described above.
5. Clamp the steering wheel in a straight-ahead
position with a clamping device designed for towing.
6. Release the parking brake.
Be sure to use the proper towing equipment designed
for recreational vehicle towing. Follow the instructions for
the towing equipment.
4-48
{
CAUTION:
Shifting a four-wheel-drive vehicle's transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P) for
an automatic transmission, or if your vehicle is
in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is firmly set before you shift the transfer
case to NEUTRAL.
If your vehicle has four-wheel-drive it cannot be dolly
towed. A four-wheel-drive vehicle must be towed
by flatbed.