Dodge RAM 1500 1998 Owner's Manual page 1380

DR
OIL PUMP (Continued)
DISASSEMBLY
(1) Remove oil pump cover screws and lift off cover
plate.
(2) Remove pump inner and outer rotors.
NOTE: Once the oil pressure relief valve, cup plug,
and pin are removed, the pump assembly must be
replaced.
(3) If it is necessary to remove the pressure relief
valve, drive the roll pin from pump housing and
remove cup plug, spring and valve.
CLEANING
(1) Wash all parts in a suitable solvent.
INSPECTION
CAUTION: Oil pump pressure relief valve and
spring should not be removed from the oil pump. If
these components
removed from the pump the entire oil pump assem-
bly must be replaced.
(1) Clean all parts thoroughly. Mating surface of
the oil pump housing should be smooth. If the pump
cover is scratched or grooved the oil pump assembly
should be replaced.
(2) Lay a straight edge across the pump cover sur-
face (Fig. 101). If a 0.025 mm (0.001 in.) feeler gauge
can be inserted between the cover and the straight
edge the oil pump assembly should be replaced.
(3) Measure the thickness of the outer rotor (Fig.
102). If the outer rotor thickness measures at 12.005
mm (0.472 in.) or less the oil pump assembly must be
replaced.
Fig. 101 Checking Oil Pump Cover Flatness
1 - STRAIGHT EDGE
2 - FEELER GAUGE
3 - OIL PUMP COVER
are disassembled
Fig. 102 Measuring Outer Rotor Thickness
(4) Measure the diameter of the outer rotor. If the
outer rotor diameter measures at 85.925 mm (3.382
in.) or less the oil pump assembly must be replaced.
and or
(5) Measure the thickness of the inner rotor (Fig.
103). If the inner rotor thickness measures at 12.005
mm (0.472 in.) or less then the oil pump assembly
must be replaced.
Fig. 103 Measuring Inner Rotor Thickness
ENGINE - 4.7L 9 - 157