What This Seal Does
This is the front main seal that rides on the bull-nose of the crankshaft, behind the damper and pulley, sealing crankcase oil at the front cover. Specs are 3.625 in inner diameter, 4.756 in outer diameter, silicone element, front position, with a dust shield built in. The shield is the detail that separates this version from the plain-lip seals in the same bore.
Failure is usually gradual. Oil weeps past the lip, gets slung by the damper, and coats the front of the block, the crank pulley, and the fan shroud. Belts pick it up and start squealing or glazing. On a chassis with a front sump pan you may see it dripping off the pan rail and get blamed on a pan gasket that is actually dry.
The silicone lip is rated for high-temperature crankcase service, and the dust shield keeps road grit off the sealing edge. That matters on a Class-8 truck running gravel yards or winter chemical, where an unshielded lip gets sandblasted and starts leaking long before the elastomer is worn out.
Why These Numbers Cross
3020183, 3020186, 213467 and 3004317 are Cummins numbers that all land on the same seal envelope for the 855 and N14 front cover. The numbers moved as the engine family evolved and as the shielded version superseded earlier plain seals, but the bore, the crank diameter and the press depth stayed the same. PAI 136018 is the aftermarket number covering that same envelope.
We list those numbers for identification only. PartStop is not affiliated with, endorsed by, or authorized by Cummins, PAI, or any other manufacturer. If your paperwork or old parts box shows any of them, 3020183 is the number to compare against.
The one thing to confirm is the dust shield. If the seal you pulled out has no shield and the front cover bore shows a shallower press, you are on an earlier configuration and need to verify by engine serial number before ordering. The cross list gets you into the right family, not to a guaranteed fit.
Before You Order
Pull the damper and look at the crank nose. A groove worn by the old lip is the most common reason a new seal leaks within a week. If the wear track is deep enough to catch a fingernail, you need a wear sleeve or a repositioned seal, not just a new seal. Check for it before the new part goes anywhere near the bore.
Get your engine serial number off the dataplate and confirm it against your application. The 855 group covers NT855, NTA855 and NH855, and the N14 and N14E are in the same lineup, but the shielded and unshielded configurations are not interchangeable in every front cover. VIN or the number stamped on the old seal settles it.
Clean the bore, install dry or with the manufacturer's specified lube only, and drive the seal square with a proper installer. Cocking it a few degrees will leak no matter how good the elastomer is. Replace the damper bolts and torque to spec while you are in there.
3020183 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3020183. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| Cummins | 3020186, 213467, 3004317 |
| PAI | 136018 |
Frequently asked questions
Is 3020183 the same seal as 3020186?
They cross to the same front seal envelope for the 855 and N14 front cover, and the numbers are listed for identification only. Dimensions are 3.625 in ID and 4.756 in OD. Confirm by your engine serial number or by the number on the seal you removed before ordering.
Does this one have the dust shield?
Yes. This version is the front crankshaft seal with integrated dust shield. The shield covers the sealing lip and keeps road grit and debris off it. If the seal you pulled out was a bare lip with no shield, verify your front cover configuration against your engine serial number first.
New seal leaked right away, what did I miss?
Almost always a grooved crank nose or a cocked install. Inspect the crank snout for a wear track cut by the old lip; if it is there, the new lip rides in the same groove and weeps. Also check that the seal was driven square to full depth with an installer, not tapped in with a punch.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
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Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.