Subaru 2009 IMPREZA Service Manual page 1884

AUTOMATIC TRANSMISSION
C: CONDITION CHECK
NOTE:
When replacing ATF, check the inside condition of transmission body by inspecting the drained ATF.
Fluid condition
Large amount of metallic pieces are
found.
Thick and varnish-form fluid.
Clouded fluid or bubbles are found in
fluid.
Automatic Transmission Fluid
Trouble and possible cause
Excessive wear of the internal of the trans-
mission body.
Burned clutch, etc.
Water mixed in fluid.
4AT-28
Corrective action
Replace ATF and check if AT operates
correctly.
Replace ATF and check the AT body or
vehicle for faulty.
Replace ATF and check the water enter-
ing point.