Hyundai Sonata 1991 Shop Manual page 402

1. Place vehicle on level floor.
2. Before removing dipstick, wipe all dirt from area around
dipstick.
3. With selector lever in "P" Park and parking brakes applied,
start engine.
4. Engine should be running at idle speed. Fluid should be at
normal operating temperature [70-80°C (16Q-1800F)].
5. Move selector lever sequentially to every position to fill
torque converter and hydraulic circuit with fluid, then place
lever in "N" Neutral position. This operation is necessary to
be sure that fluid level check is accurate.
6. Check. to see if fluid level is in "HOT" range on dipstick. If
fluid is low, add automatic transaxle fluid until level reaches
"HOT" range.
Low fluid level can cause a variety of conditions because it
allows pump to take in air along with fluid. Air trapped in
hydraulic circuit forms bubbles which make fluid spongy.
Therefore, pressure will be erratic.
Improper filling can also raise fluid level too high. When
transaxle has too much fluid, gears churn up foam and cause
same conditions which occur with low fluid level. resulting
in accelerated deterioration of automatic transaxle fluid. In
either case, air bubbles can cause overheating, fluid
oxidation, and varnishing, which can interfere with normal
valve, clutch, and servo operation. Foaming can also result
in fluid escaping from transaxle vent where it may be
mistaken for a leak.
Along with fluid level, it is important to check the condition
of the fluid. When fluid smells burned, and is contaminated
with metal bushing or friction material particles, a complete
transaxle overhaul is needed. Be sure to examine fluid on
dipstick closely. If there is any doubt about its conditions,
drain out sample for double check. After fluid has been
checked, seat dipstick fully to seal out water and dirt.
DIAGNOSIS AND TEST
FLUID LEVEL AND CONDITION
GENERAL
Y45CH18
45-13