The order we never skip — which is why the wrong part does not reach your site.
01
Confirm
Nameplate, OEM number and working conditions — checked against your machine, confirmed in writing before you pay.
02
Verify
Photos and video of the actual part, packed and labelled, before it leaves. What you see is what ships.
03
Prevent
Send the hour-meter reading and we log the service interval — you get a message before the next one is due.
04
Dispatch
Nothing leaves Xi’an until you reply "ok". You approve, then we ship — not the other way round.
Confirm this part for my machine
Machine model and part number are what let us confirm fitment in writing. Message is optional.
Overview
Fitment Note: Confirmed by the removed seal number and the flywheel housing bore. OD 150 mm. The seal is fitted with a driver and must sit square - send the housing bore if you are unsure.
Specifications
MOQ
10 pcs
Type
Rear Crankshaft Seal
Engine
CAT 3066 / S6K / C6.4
Material
NBR Rubber Lip / Metal Case
Position
Crankshaft rear (flywheel housing)
Replaces
CAT 5I-7660
Shipping
Rail / Sea / Air
Warranty
12 Months
Lead Time
15-30 Days
Type Seal
Flywheel housing lip seal
Application
CAT 312C / 320C / 320D / 323D
Outer Diameter
150 mm
Aftermarket rear crankshaft seal (flywheel housing lip seal) 5I-7660A — a direct replacement for the Caterpillar 5I-7660 seal. It fits the Caterpillar 3066 / S6K / C6.4 diesel engine family (also 3064 / C4.2), commonly used on CAT 312C / 320C / 320D / 323D excavators. Outer diameter 150 mm.
The rear crank seal sits in the flywheel housing and seals the back of the crankshaft. When the lip hardens or wears, engine oil leaks between the engine and the transmission — oil appears at the bell-housing joint / inspection cover, the clutch (if fitted) gets contaminated, and oil loss increases. It is normally renewed when the flywheel housing or transmission is off.
NBR (nitrile) rubber lip in a metal case; the blue outer ring is the seal carrier. Confirm the removed seal number and the housing bore before ordering; the seal is fitted with a driver and must sit square.
Key Features
Direct replacement for CAT 5I-7660
Outer diameter 150 mm, lip-type flywheel housing seal
Oil leaking at the engine / transmission joint, oil at the bell housing / inspection cover, increased oil consumption; on clutch machines it contaminates the clutch.
Installation Tips
1. Clean the flywheel housing bore and the crankshaft rear flange; remove old seal residue.
2. Lubricate the seal lip with clean engine oil.
3. Press the seal in squarely with a proper driver until it seats; do not distort the lip.
4. Check the seal runs true on the crankshaft before refitting the flywheel.
