GMC 1997 Safari Owner's Manual page 350

I
Short WiplCity Maintenance Schedule
I
90,000 Miles
(150 000
km)
0
Change engine oil and filter (or every
3 months, whichever occurs first).
An Emission Control Service.
0
Lubricate chassis components (or every
3 months, whichever occurs first).
(See footnote
#.)
0
Check rear/front axle fluid level and add
fluid as needed. Check constant velocity
joints and axle seals for leaking.
(See footnote
**.)
0
For Two-Wheel-Drive vehicles only: Clean
and repack the front wheel bearings (or at
each brake relining, whichever occurs first).
0
Change automatic transmission fluid and
filter if the vehicle is mainly driven under
one or more of these conditions:
- In heavy city traffic where the outside
temperature regularly reaches
90
O
F
(32°C) or higher.
-
In hilly or mountainous terrain.
- When doing frequent trailer towing.
-
Uses such as found in taxi, police or
delivery service.
If you do not use your vehicle under any of these
conditions, change the fluid and filter every
30,000 miles (50 000 krn).