Cadillac 2017 CT6 Owner's Manual page 321

320 Service and Maintenance
Any vehicle consistently
operated in a high sand or
dust environment such as
those used on oil pipelines
and similar applications.
Vehicles that are regularly used
for short trips of 6 kilometers
or less
If your vehicle has an Oil Life
Indicator, the indicator will show
you when to change the oil and
filter. Under severe conditions
the indicator may come on
before 10 000 km/6,000 mi. The
indicator won't detect dust in the
oil, so if you drive in a dusty
area you may have to change
the oil and filter sooner than
every 10 000 km/6,000 mi.
Note: All vehicles with
rear-wheel drive change
driveline axle oil every
30 000 km/19,000 mi if vehicle is
used for towing purposes.
* Footnote: Under extreme
driving conditions listed above, it
may be necessary to replace
your spark plugs at more
frequent intervals. For further
assistance in determining the
most suitable service
maintenance intervals for your
vehicle, please contact your
authorized GM Dealer.
Additional Required
Services Severe Service
Every 72 000 km/45,000 mi
Change automatic transmission
fluid and filter.
Rear axle fluid (If equipped with
limited slip).
Every 80 000 km/50,000 Miles
All-wheel-drive vehicles only:
Transfer case fluid change.
During any maintenance, if a
power washer is used to clean
mud and dirt from the
underbody, care should be taken
to not directly spray the transfer
case output seals. High pressure
water can overcome the seals
and contaminate the transfer
case fluid. Contaminated fluid
will decrease the life of the
transfer case and should be
replaced.