What This Seal Does
This is the front main seal that rides on the crankshaft snout inside the front cover bore. It is the bull-nose style with no separate dust shield, so the sealing lip and the outer case are one piece pressed into the bore. Inner diameter is 3.625 in, outer diameter is 4.756 in, and the element is silicone.
It sees constant heat off the front of the block and whatever crankcase pressure the engine is making. Silicone holds its lip tension better than nitrile at sustained high oil temperature, which is why the 855 and N14 platforms went that direction on the front position.
Applications listed for this seal are Cummins NT855, NTA855, NH855, and N14 / N14E engines in Class-8 chassis. That covers a lot of Kenworth W900 and T800 iron plus Volvo VNL. Engine serial number is what settles it, not the truck badge.
Why These Numbers Cross
Cummins 213467 and 208579 are earlier and superseding references for the same front seal envelope on the 855 family. Cummins revised the seal material and packaging over the life of the engine without changing the bore or the shaft diameter, so the numbers stack onto one physical part rather than several.
National 39703 is the bearing-and-seal industry number for the same 3.625 in shaft by 4.756 in bore dimension in this lip configuration. PAI 136000 is the aftermarket engine-parts number for the same seal. Different catalogs, same three dimensions and same lip geometry.
That is the whole basis of the cross: shaft diameter, bore diameter, and lip style. If your old seal measures out to those numbers and has no dust shield, this is the same seal. If yours has a wear sleeve or a separate slinger, you are looking at a different front cover setup and this cross does not apply.
Before You Order
Pull the number off the old seal case or the crate it came in and get your engine serial number. Cross-reference is a starting point, not a fitment promise. Confirm by VIN or by the number stamped on the part you are replacing before you commit to the repair.
Check the crank snout for a groove worn by the old lip. A ridge you can catch with a fingernail will leak a new seal in short order. Check the front cover bore for scoring and for the previous seal's install depth, and inspect the damper and front cover alignment while it is apart. Blocked crankcase breather pressure kills front seals fast.
3006736 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3006736. 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 | 213467, 208579 |
| National | 39703 |
| PAI | 136000 |
Frequently asked questions
Is 3006736 the same seal as 213467?
They cross to the same front crankshaft seal on the 855 and N14 family. 213467 is a Cummins reference number listed for identification. Measure your old seal at 3.625 in inner and 4.756 in outer and confirm it is the bull-nose style with no dust shield before ordering.
How do I know if I have the bull-nose front seal or the later style?
Pull the damper and look at the seal face. The bull-nose seal is a single-piece unit with no separate dust shield or wear sleeve riding the crank snout. If you find a pressed-on sleeve or a slinger, your front cover is set up for a different seal and this number is not the one you want.
Why did my new front seal leak again after a few thousand miles?
Usually crankcase pressure or a worn crank snout. Check the breather and blowby first, then feel the snout for a wear groove from the old lip. Installing the new seal at a slightly different depth in the bore can move the lip off a worn track and buy you a clean sealing surface.
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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