OIL PUMP
DESCRIPTION
The oil pump is located in the pump housing inside
the bell housing of the transaxle case (Fig. 258). The
oil pump consists of an inner and outer gear, a hous-
ing, and a cover that also serves as the reaction shaft
support.
OPERATION
As the torque converter rotates, the converter hub
rotates the inner and outer gears. As the gears
rotate, the clearance between the gear teeth
increases in the crescent area, and creates a suction
at the inlet side of the pump. This suction draws
fluid through the pump inlet from the oil pan. As the
clearance between the gear teeth in the crescent area
decreases, it forces pressurized fluid into the pump
outlet and to the valve body.
STANDARD PROCEDURE - OIL PUMP VOLUME
CHECK
Measuring oil pump output volume will determine
if sufficient flow to the transmission oil cooler exists,
and whether or not an internal transmission failure
is present.
Verify that transmission fluid is at the proper
level. If adding fluid is necessary, fill to the proper
level with Mopart ATF+4 (Automatic Transmission
Fluid–Type 9602). The following procedure is to
check oil pump output volume:
(1) Using hose cutters or a suitable blade, cut the
“to cooler” (Fig. 259) line off flush with the cooler
inlet fitting and place a collection container under
the open line.
CAUTION: With the fluid set at the proper level,
fluid collection should not exceed (1) quart or inter-
nal damage to the transmission may occur.
(2) Start engine and run at curb idle speed, with
the shift selector in neutral.
(3) If one quart of ATF is collected in 20 seconds or
less, flow is within acceptable limits. If fluid flow is
intermittent or it takes more than 20 seconds to col-
lect one quart of ATF, (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 41TE -
DIAGNOSIS AND TESTING).
(4) Inspect the cooler hose for damage. Replace if
necessary.
(5) Re-connect the to cooler line to the transmis-
sion using a service splice kit. Refer to instructions
inclued with the kit.
(6) Refill the transaxle to proper level with
Mopart ATF+4 (Automatic Transmission Fluid–Type
9602).
Fig. 258 Oil Pump Assembly
1 - PUMP HOUSING
2 - OUTER PUMP GEAR
3 - INNER PUMP GEAR
4 - REACTION SHAFT SUPPORT
5 - SEAL RINGS (4)
6 - REACTION SHAFT
7 - CRESCENT
Fig. 259 Transaxle Oil Cooler Fittings
1 - FROM COOLER
2 - TO COOLER
21s - 170 41TE AUTOMATIC TRANSAXLE PL
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