GMC C-Series 2001 Owner's Manual page 181

4. Remove the remaining slack in the lift chains.
The tow bar swing arm should rest against
the 2 x 12 x 40 hardwood board as shown.
A. Hardwood Board
5. Raise the vehicle to the required height.
5-14
B. Swing Arm
Single Drive Rear Axle
Disconnect the propshaft at the rear axle. Secure the
propshaft to the frame or crossmember.
Tandem Drive Rear Axles (Forward Axle
Off the Ground)
Raise the front of the vehicle until the forward
tandem axle wheels are off the ground. Remove the
rearward propshaft.
Tandem Drive Rear Axle (Both Axles on the Ground
Due to Type of Suspension or Attached Load)
Disconnect the propshaft at the forward tandem axle.
Secure the propshaft to the frame or crossmember.
If there is damage or suspected damage to the axle(s),
remove all axle shafts. Cover the hub openings to
prevent the loss of lubricant or entry of dirt or
foreign objects.
After Towing
Block the rear wheels and install axle and propeller
shafts. Check for proper phasing of universal joints.
Apply the emergency brake system before disconnecting
from the towing vehicle. Check and fill the rear axle
with oil as required.