Product Description
Interstate-McBee M-3949688 CP3 Rectangular Ring Seal – 03–18 5.9L/6.7L Cummins
Direct-fit rectangular-profile ring seal for the CP3 fuel injection pump gear access cover on Cummins B-Series engines. This Interstate-McBee aftermarket replacement matches the OEM Cummins 3949688 specification for reliable, leak-free sealing on 2003–2018 5.9L & 6.7L applications.
- Purpose-built: Seals the CP3 gear access cover (Cummins cover P/N 4935281).
- OEM-style fit: Interchangeable with Cummins 3949688 for quick, hassle-free installs.
- Durable elastomer: Rectangular cross-section helps maintain sealing in the cover groove.
- Great value: Interstate-McBee quality at an aftermarket price point.
Specifications
| Interstate-McBee Part | M-3949688 |
|---|---|
| OEM Cross-Reference | Cummins 3949688 |
| Related Component | CP3 Gear Access Cover — Cummins 4935281 |
| Application | CP3 fuel injection pump gear access cover seal |
| Material | Fuel/oil-resistant elastomer (rectangular profile) |
| Included | (1) Rectangular ring seal |
Vehicle Fitment
Always verify by VIN/ESN for edge cases and build-date changes.
- Ram 2500/3500, 5.9L Cummins (CP3): 2003–2007
- Ram 2500/3500, 6.7L Cummins (CP3): 2007.5–2018
- Ram 4500/5500, 6.7L Cummins (CP3): 2008–2018
- Not for CP4-equipped systems (certain later 2019–2020 models).
Install Notes
- Clean the cover and housing groove; remove all old material and debris.
- Lightly lubricate the seal with clean engine oil before installation.
- Install cover and tighten fasteners to factory torque using the Cummins service manual.
Warranty
Interstate-McBee new engine parts typically carry up to 24 months coverage; fuel-injection items are generally 12 months. Coverage for this seal follows manufacturer policy; contact us if you need specifics for your application.
Why Buy From CPP Diesel
- ESN-verified fitment support from real diesel techs.
- Fast shipping and easy returns.
- One-stop shop for CP3 service parts, covers, bolts, and related seals.
FAQ
Is this the seal under the CP3 gear access cover?Yes. This rectangular ring fits beneath the CP3 gear access cover (Cummins 4935281) on CP3-equipped 5.9L/6.7L engines.
Will it fit both 5.9L and 6.7L Cummins?
Yes—fits 2003–2007 5.9L CP3 and 2007.5–2018 6.7L CP3 applications (including many Ram 2500/3500/4500/5500 models).
Can I reuse the old seal?
Re-use is not recommended. Replace the seal any time the cover is removed to help prevent leaks.
Is this compatible with CP4 trucks?
No. It’s designed for CP3 systems. CP4-equipped models use different sealing components.
Product Videos
Custom Field
YEAR 2003-2018
MAKE DODGE
ENGINE 5.9L,6.7L
