Cadillac CTS Owner's Manual page 328

All-wheel-drive vehicles only:
Transfer case fluid change
(severe operation) for vehicles
mainly driven in heavy city traffic
in hot weather, in hilly or
mountainous terrain, when
frequently towing a trailer,
or when used for taxi, police,
or delivery service. During any
maintenance, if a power washer
is used to clean mud and dirt
from the underbody, care should
be taken. Do not directly power
wash the transfer case and/or
front/rear axle output seals. High
pressure water can overcome
the seals and contaminate the
fluid. Contaminated fluid will
decrease the life of the transfer
case and/or drive axles and
should be replaced.
Additional Maintenance Every
60 000 km
Replace brake fluid every
60 000 km or two years,
whichever occurs first.
Additional Maintenance Every
72 000 km
Automatic transmission fluid and
filter change (severe operation)
for vehicles mainly driven in
heavy city traffic in hot weather,
in hilly or mountainous terrain,
when frequently towing a trailer,
or when used for taxi, police,
or delivery service.
Spark plugs replace. (2.0L
LTG Turbo Engine)
Rear axle fluid (6.2L V8 LT4
Engines only).
Rear axle fluid (severe
operation).
Front axle fluid (severe
operation). If equipped
with AWD.
Additional Maintenance Every
150 000 km or if Necessary
Spark plugs replace. (6.2L
LT4 Engine)
Service and Maintenance
Additional Maintenance Every
250 000 km or Every Five
Years, Whichever Occurs First
Engine cooling system drain and
refill.
Conditions Requiring More
Frequent Maintenance (Severe
Service)
Extreme temperatures.
Heavy city traffic.
Hilly or mountainous terrain.
Dusty, muddy or off-road
conditions.
Commercial use or trailer towing.
Most trips less than 6 km.
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