Product Description
CUMMINS 3920691 OEM PISTON PIN RETAINING RING (WRIST PIN CLIP) – RAM 5.9L (1989–2007)
The CUMMINS 3920691 OEM PISTON PIN RETAINING RING is the small but critical wrist pin clip that keeps your piston pin securely locked in the piston on 1989–2007 Dodge/Ram 2500/3500 trucks with the 5.9L Cummins. This genuine Cummins piston pin retaining ring / circlip is engineered for precise groove fit and long-term retention under heavy load, high RPM, towing, sled-pull, or work-truck duty.
Designed for the Cummins B-series 5.9L platform, this retaining ring is specified across 12-valve, VP44 24-valve, and common-rail 5.9L applications, as well as many industrial and Euro 3 B-series engines where 3920691 is called out from the factory. Two clips are used per piston – one on each side of the wrist pin – so a complete 6-cylinder 5.9L engine requires 12 clips total.
WHY CHOOSE GENUINE CUMMINS 3920691?
- OE-grade spring steel retaining ring designed specifically for the 5.9L Cummins wrist pin groove.
- Direct-fit replacement for factory clips – no guesswork on size or shape.
- Helps prevent catastrophic pin walk and piston/liner damage on performance or work-truck builds.
- Used on a wide range of Cummins 5.9L B-series and Euro 3 applications (verify by ESN).
- Perfect match for OEM piston kits, ring sets, and connecting rod bushings.
QUICK SPECS
- Brand: Cummins (Genuine OEM)
- OE Part #: 3920691
- Component: Piston pin retaining ring / wrist pin clip (circlip)
- Qty Required (per engine): 2 clips per piston – 12 clips per 6-cylinder 5.9L engine
- Material: Hardened spring steel
- Primary Platform: Cummins B-series 5.9L / ISB 5.9
FITMENT
Automotive – Dodge/Ram 5.9L Cummins
Verified primary fitment (automotive):
- 1989–1998 Dodge/Ram 2500 & 3500 – 5.9L 12-valve 6BT
- 1998.5–2002 Dodge/Ram 2500 & 3500 – 5.9L 24-valve ISB (VP44)
- 2003–2007 Dodge/Ram 2500 & 3500 – 5.9L 24-valve ISB (common-rail)
This clip is specified anywhere Cummins lists part #3920691 for the piston pin retaining ring in the piston assembly. Always confirm by engine serial number (ESN) and build data when working with swapped or mixed components.
Industrial / Off-Highway / B-Series Applications
The 3920691 retaining ring is also used across many Cummins B-series engines including 4B3.9, 6B5.9, 6C8.3, ISB/ISD/ISF, and certain Euro 3 / Euro 4 rated engines, as well as industrial and generator packages where 3920691 appears in the piston/pin assembly or related kits. Verify ESN and parts list before ordering for non-automotive applications.
CROSS-REFERENCE & RELATED CUMMINS PARTS (INTERNAL LINKS)
Pair this retaining ring with the correct Cummins piston kits, ring sets, and bushings for a complete, OE-level rebuild:
- CUMMINS 4891178 OEM CONNECTING ROD WRIST PIN BUSHING – RAM 5.9L (1989–2007) – OEM wrist pin bushing for 5.9L B-series builds.
- CUMMINS 3802421 OEM PISTON RING SET (STANDARD) – RAM 5.9L 12V/24V (1989–2002) – standard-bore OE ring set for 5.9L engines.
- CUMMINS 3802160 OEM ENGINE PISTON KIT (MARINE STYLE BOWL, STANDARD BORE) – 5.9L 12V 6BT (1989–1998) – marine-style standard-bore piston kit with pin & clips.
- CUMMINS 3802132 OEM ENGINE PISTON KIT – .020 OVER (MARINE-STYLE BOWL) – 5.9L 12V 6BT (1989–1998) – .020" over marine-style piston kit, includes wrist pin & retainers.
- CUMMINS 4089669 OEM ENGINE PISTON KIT (STANDARD) – RAM 5.9L (2004.5–2007) – late common-rail piston kit with matching wrist pin & clips.
WHAT’S INCLUDED
- (1) Genuine Cummins piston pin retaining ring / wrist pin clip – part #3920691
Order quantity: 2 clips per piston (12 clips per 6-cylinder 5.9L engine).
INSTALL TIPS
- Always wear eye protection – these spring-steel clips can snap during installation or removal.
- Verify you have the correct piston, pin, and groove combination before installation.
- Install the clip fully in the groove; check that the ends are properly seated and cannot rotate out.
- Lubricate the wrist pin and bushing with assembly lube before final assembly.
- Rotate the engine by hand after assembly to confirm smooth pin and piston motion with no binding.
SPECIFICATIONS FOR CUMMINS 3920691
| Attribute | Value |
|---|---|
| Brand | Cummins (Genuine OEM) |
| Part Number | 3920691 |
| Component | Piston pin retaining ring / wrist pin clip (circlip) |
| Platform / Engine Family | Cummins B-series 5.9L (ISB/6BT) and related B-series variants where 3920691 is specified |
| Primary Automotive Fitment | 1989–2007 Dodge/Ram 2500/3500 with 5.9L Cummins (12V, VP44 24V, and common-rail 24V) |
| Qty Required per 5.9L Engine | 12 clips (2 per piston × 6 pistons) |
| Material | Hardened spring steel |
| Cross Reference Notes | Used in various Cummins piston kits and assemblies (e.g. kits including marine and standard 5.9L pistons). Often paired with Cummins piston kits 3802160 / 3802132 and ring set 3802421 when these assemblies call out 3920691. Also referenced in certain service kits for 4B3.9 and 6B5.9 B-series engines. |
| UPC | Not specified / not published by manufacturer for this small hardware service part. |
| GTIN | Not specified / not published by manufacturer. |
| E-Codes / Emissions Notes | Internal engine hardware; not individually emissions-certified. Follow OE service procedures for emissions compliance. |
| Approx. Part Weight | ~0.012 lb (0.005 kg) per clip (shipping weight may vary slightly with packaging). |
| Approx. Package Dimensions | Approx. 4.4 cm × 4.4 cm × 0.3 cm (single-clip service package). |
| Shipping Info | Ships as small parcel; typically combined with other engine parts in a single shipment to reduce freight cost. |
| Country of Origin | As marked on Cummins packaging (varies by production batch). |
| Prop 65 Warning | This product may contain chemicals known to the State of California to cause cancer and reproductive harm. For more information, visit www.P65Warnings.ca.gov. |
FAQ
WILL THIS CLIP FIT MY 1989–2007 5.9L CUMMINS RAM?In most cases, yes. Cummins 3920691 is used across 5.9L B-series applications from 1989–2007, including 12-valve, VP44 24-valve, and common-rail engines where this part number is specified. Always confirm by engine serial number (ESN) and piston/pin part numbers before ordering.
HOW MANY RETAINING RINGS DO I NEED FOR A COMPLETE 5.9L ENGINE?
Each piston uses two clips (one on each side of the wrist pin), so a complete 6-cylinder 5.9L requires 12 clips total. Order at least 12, plus a couple of spares if you anticipate any lost or damaged during installation.
IS CUMMINS 3920691 A GENUINE OEM PART OR AFTERMARKET?
This listing is for the genuine Cummins 3920691 retaining ring in Cummins packaging. CPP Diesel also stocks high-quality aftermarket equivalents for budget builds, but this SKU is the OEM clip.
DOES THIS CLIP ALSO WORK ON 6.7L CUMMINS ENGINES?
3920691 appears on many B-series and Euro 3 B-engine applications, but not all 6.7L engines use this same clip. Some ISB 6.7 / B6.7 variants may specify 3920691, while others use different piston and pin combinations. Always confirm by ESN and piston/pin part number for 6.7L builds.
WHAT CUMMINS PARTS SHOULD I BUY WITH THESE RETAINING RINGS?
For a typical 5.9L overhaul, customers often buy matching piston kits, ring sets, and wrist pin bushings. Popular combinations include Cummins piston kits like 3802160 or 3802132, ring sets like 3802421, and the 4891178 connecting rod wrist pin bushing, along with full gasket sets and bearings.
CAN I REUSE MY OLD WRIST PIN CLIPS?
It is strongly recommended to replace wrist pin clips any time pistons and pins are removed. Reusing old clips can increase the risk of loss of tension, pin walk, and major engine damage. At this price point, new OEM clips are cheap insurance on a fresh build.
