GMC 1994 Yukon Owner's Manual page 237

A
CAUTION:
Getting under
a
vehicle when it
is
jacked up
is dangerous. If the
vehicle
slips off the jack, you could be badly injured or killed.
Never get under a vehicle when it is supported only by a jack.
NOTICE:
Raising your vehicle with the jack improperly positioned will
damage the vehicle or may allow the vehicle to fall off the jack.
Be sure to fit the jack lift head into the proper location before
raising your vehicle.
Front Position
Rear Position
Raise the vehicle by rotating the ratchet to the right. Make sure the UP
marking faces you. Use the jack handle extentions if the flat is on the rear
of
the vehicle. Raise the vehicle far enough off the ground so there is enough
room for
the
spare tire to fit.
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