GMC TopKick 2007 Owner's Manual page 376

Air brake automatic slack adjuster service (or
every 500 hours, whichever occurs first). (33)
Check air brake relay valve operation and check
for leaks (or every month, or every 300 hours,
whichever occurs first).
Clean air brake application valve (or every
3 months, or every 300 hours, whichever
occurs first). Lubricate linkage.
Air brake chamber service (or every 2 months,
whichever occurs first). (34)
Air brake system valve service (or every
3 months, or every 900 hours, whichever
occurs first). (37)
Rear axle air shift motor service. (10)
Air intake system service (or every 24 months,
whichever occurs first). (3) (4) (23)
Evaporative Control System service, if
equipped, (or every 24 months, whichever
occurs first). (2) (24) †
376
72,000 Miles (115 000 km)
Isuzu 6H Diesel Without Engine Oil Life System
Only: Change engine oil and filter (or every
12 months, or every 600 hours of engine
operation, whichever occurs first). (2)
Isuzu 6H Diesel With Engine Oil Life System
Only: Check oil life system (or every 12 months,
or every 600 hours of engine operation,
whichever occurs first). If engine oil and filter
are changed, reset system. See "Engine Oil
®
(DURAMAX /Isuzu Diesel)" in the Index. (2) (7)
Lubricate U-joints (or every 6 months,
whichever occurs first).
75,000 Miles (120 000 km)
Gasoline Engine Only: Check engine oil life
system. If engine oil and filter are changed,
reset system. See "Engine Oil (Gasoline
Engine)" in the Index. (2) (8)
®
6.6L DURAMAX Diesel Without Engine Oil
Life System Only: Change engine oil and
filter (or every 12 months, or every 750 hours
of engine operation, whichever occurs first). (2)