DESCRIPTION & OPERATION
Page 49
OIL PUMP
Due to the addition of an idler gear, the auxiliary
shaft on the E-Tech™ engine turns the opposite
direction of the E7 auxiliary shaft. In order for the
E-Tech™ oil pump to turn the same direction as
the E7 pump, the gear set helixes are different.
On the E-Tech™, driving thrust load of the shaft
pumping gears is toward the pump housing and
not toward the pump cover, as with the E7
engine. Refer to Figure 54.
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An improper drive gear on the oil pump will
prevent oil pump installation, assuming a
correct gear is on the auxiliary shaft.
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If an oil pump and an auxiliary shaft
assembly were replaced, two improper
gears could be installed, and engine failure
would result.
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In replacing any of these critical parts,
always refer to part number information in
the MACK Parts System to ensure the
correct component is being used.
54
Figure 54 — Oil Pump Drive Gears
The E-Tech™ auxiliary shaft speed or rpm is 22%
faster than that of the E7. As a result, the
E-Tech™ oil pump (which has slower ratio oil
pump gears) turns 6% faster than the E7. This
provides increased lubricating capacity. Also, the
auxiliary shaft used on the E-Tech™ engine
(Figure 55) is through-drilled to carry oil to the
rear auxiliary shaft bushing. This is different from
the E7 engine, which provides oil to the rear
bushing through a cylinder block oil passage.
The E-Tech™ auxiliary shaft is identified by three
painted stripes (early production) or three
machined circumferential cuts (later production)
in front of the stamped part number.
55
Figure 55 — Auxiliary Shaft
1. E7 Oil Pump Gear
(12 Teeth)
2. E7 Aux. Pump Gear
(18 Teeth)
3. E-Tech™ Oil Pump Gear
(13 Teeth)
4. E-Tech™ Aux. Shaft
Gear (17 Teeth)
5_106_00.bk Page 49 Friday, August 4, 2000 11:17 AM
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