Product Description
The Cummins 3949326 OEM Ring Dowel is the factory alignment dowel used between the front gear housing and cylinder block on ISB 5.9L and 6.7L Cummins engines (2003–2018). This precision-machined locating dowel ensures correct front cover alignment, which is critical for geartrain timing accuracy, front seal life, and overall engine reliability. Using a genuine Cummins alignment dowel eliminates the risk of misalignment that can occur with worn, missing, or incorrect aftermarket hardware.
This ring-style dowel is commonly replaced during engine rebuilds, front cover service, gasket replacement, or anytime the gear housing is removed. For long-term sealing and correct mechanical timing, only OEM Cummins dowels should be used.
Fitment
- 2003–2007 Dodge Ram 2500/3500 with 5.9L ISB Cummins
- 2007.5–2018 Dodge Ram 2500/3500 with 6.7L ISB Cummins
- ISB 5.9L and ISB 6.7L engines in industrial, agricultural, and vocational equipment (ESN-specific)
- Required anytime the factory front gear housing is removed or serviced
Note: Industrial applications vary by ESN — verify before ordering.
Cross-Reference (Cummins-Only)
Related Cummins hardware commonly replaced during front gear housing service:
• Cummins 3900625 OEM Hex Flange Head Cap Screw
• Cummins 3915104 OEM Regular Hexagon Nut – ISB Hardware
• Cummins 3915787 OEM Threaded Plug – Oil Filter Housing
FAQ
What does the Cummins 3949326 ring dowel do?
The dowel precisely aligns the front gear housing to the engine block, ensuring proper geartrain operation and sealing.
Do I need new dowels when reinstalling the front gear housing?
Yes. Cummins recommends replacing dowels that are worn, damaged, or loose. New OEM dowels ensure accurate alignment.
Does this fit both 5.9L and 6.7L ISB engines?
Yes — 2003–2018 ISB 5.9L and ISB 6.7L engines use this style of alignment dowel.
Can poor alignment cause oil leaks?
Absolutely. Misalignment of the housing can cause front main seal leaks and premature wear in the timing geartrain.
Is this the same as the dowel used on 12-Valve engines?
No. Earlier B-Series engines often use different dowel dimensions and part numbers. This one is correct for ISB platforms only.
Specifications for cummins 3949326
| Specification | Value |
|---|---|
| Brand | Cummins Genuine Parts |
| Part Number | 3949326 |
| Component Type | Ring Dowel – Alignment Locating Pin |
| UPC | Not Published |
| GTIN | Not Published |
| Cross Reference | Used across ISB gear housing/block alignment assemblies |
| E-Codes | N/A |
| Shipping Weight | 0.05 lbs |
| Package Dimensions | 1 x 1 x 1 in |
| Prop 65 Warning | Not Applicable |
