Cadillac 1998 Seville Owner's Manual page 295

To get the right reading, the fluid should be at normal
operating temperature, which is 180°F to 200°F (82°C
to 93°C).
Get the vehicle warmed up by driving about 15 miles
(24
km)
when outside temperatures are above 50°F
(10°C). If it's colder than 50°F
(
10°C), you may have
to drive longer.
Checking the Fluid Level
a
0
Park your vehicle on a level place. Keep the
engine running.
With the parking brake applied, place the shift
lever in PARK (P).
With your
foot
on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).
Let the engine run at idle for three to five minutes.
Then, without shutting off the engine, follow these steps:
The transaxle fluid cap is
located next to the radiator
hose and below the air
cleaner assembly on the
driver's side of the engine.
Remove the
air
cleaner assembly so you can reach the
transaxle fluid cap. Turn the cap to the left to remove.
Pull out the dipstick and wipe it with a clean rag or
paper towel.
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