Product Description
CUMMINS 3938156 OEM TIMING GEAR HOUSING GASKET – 5.9L 12V/24V (1989–2002)
The CUMMINS 3938156 OEM timing gear housing gasket is the genuine gear housing-to-block gasket used on most 1989–2002 5.9L Cummins engines. When you pull the front gear housing to fix a Killer Dowel Pin (KDP) issue, reseal the timing case, or swap housings, this is the gasket that restores a clean, leak-free seal between the gear housing and the engine block. No guessing, no universal material—just proven Cummins genuine parts backed by OE engineering.
Instead of chasing oil film down the front of the engine, bolt it back together with the correct gear housing gasket. Pair this gasket with a new CUMMINS 3918673 timing gear case front cover gasket and a fresh CUMMINS 3937111 front crankshaft seal kit for a complete front-of-engine reseal that’s built to last.
Key Benefits
- Genuine Cummins 3938156 – not a generic or “will-fit” aftermarket gasket.
- Correct material and profile for the gear housing-to-block joint to keep oil where it belongs.
- Verified fit for 1989–2002 Ram 2500/3500 5.9L (12V & 24V/VP44) plus BS3/B-Series industrial engines (verify by ESN).
- Perfect for KDP repair and any timing case housing service where the gear housing is removed.
- Designed by Cummins to maintain geartrain alignment and sealing performance in severe-duty use.
Fitment
Automotive – Dodge Ram
- 1989–1993 Ram 2500 / 3500 – 5.9L 12V Cummins (6BT)
- 1994–1998 Ram 2500 / 3500 – 5.9L 12V Cummins (P7100 “P-pump”)
- 1998.5–2002 Ram 2500 / 3500 – 5.9L 24V ISB Cummins (VP44)
Industrial / Off-Highway & Global B-Series
Cummins lists this gasket for a wide range of B-Series and ISB/QSB engines, including 4B3.9, 6B5.9, ISB 5.9/6.7, and related variants used in vocational trucks, buses, agriculture, and construction equipment. Always confirm fitment by engine serial number (ESN) before ordering for non-Ram applications.
Position: Between the timing gear housing and the engine block (this is NOT the front cover gasket).
Recommended Cummins Companion Parts
- CUMMINS 3936256 OEM TIMING GEAR CASE HOUSING – 5.9L 12V (1994–1998) – Direct-fit inner gear housing for P-pump 12V engines.
- CUMMINS 3914385 OEM TIMING GEAR HOUSING COVER GASKET – 5.9L 12V (1989–1993) – Front/timing cover gasket for early 12V applications.
- CUMMINS 3918673 OEM TIMING GEAR CASE FRONT COVER GASKET – 5.9L (1994–2002) – Gear cover-to-housing gasket for later 12V/24V engines.
- CUMMINS 3941759 OEM TIMING GEAR COVER – 5.9L 24V (1998.5–2002) – OE front timing cover for VP44 24V trucks.
- CUMMINS 4939587 OEM ENGINE OIL PUMP – 5.9L 12V/24V (1989–2002) | 4BT/6BT – Genuine Cummins oil pump commonly serviced with front-of-engine work.
- CUMMINS 3937111 FRONT CRANKSHAFT SEAL SERVICE KIT – 5.9L CUMMINS (1989–2007) – OE front main seal kit; ideal to replace any time the housing and cover are off.
Installation Notes
- Thoroughly clean the engine block and gear housing mating surfaces; remove all old gasket material and sealant without gouging the metal.
- Dry-fit the housing on the block to confirm dowel alignment before final assembly.
- Use the correct Cummins-approved sealant only where specified (corners and joints) – do not coat the entire gasket.
- Torque the housing bolts in sequence to factory spec and re-check after the first heat cycle if required by the service manual.
- With the housing off, inspect and secure the Killer Dowel Pin (KDP) and related hardware.
Specifications for cummins 3938156
| Brand | Cummins Genuine Parts |
| Part Number | 3938156 |
| Product Type | Timing gear housing-to-block gasket (gear housing gasket) |
| Engine Application | 5.9L 12V & 24V Cummins (B-Series / ISB) and related BS3/B-Series engines – verify by ESN |
| Primary Vehicle Fitment | 1989–2002 Dodge Ram 2500/3500 with 5.9L Cummins (12V & 24V VP44) |
| Quantity Required | 1 per engine |
| Shipping Weight (approx.) | 0.25 lb (0.11 kg) |
| Package Dimensions (approx.) | Length 18.00 in × Width 14.00 in × Height 0.13 in |
| Cross Reference / Related Cummins Parts | Timing gear case housings: 3920758 (’89–’93), 3936256 (’94–’98); Front cover gaskets: 3914385 (’89–’93), 3918673 (’94–’02); Front timing cover: 3941759 (’98.5–’02 24V); Front crank seal kit: 3937111; Engine oil pump: 4939587. Always confirm latest supersessions in Cummins service information. |
| GTIN | Not specified in publicly available Cummins catalogs |
| UPC | Not specified in publicly available Cummins catalogs |
| E-Codes / Emissions Notes | Used on BS3/B-Series 5.9L and various ISB/QSB engine families; emissions certification depends on engine platform and ESN. |
| Prop 65 Warning | This product can expose you to chemicals including petroleum-based and metallic components, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov. |
Frequently Asked Questions
Will this Cummins 3938156 gasket fit my 1989–2002 Ram 5.9L Cummins?
For most 1989–2002 Ram 2500/3500 trucks with the 5.9L Cummins (12V or 24V/VP44), this is the correct OEM gear housing-to-block gasket. Because some early applications and industrial engines vary, CPP Diesel always recommends confirming with your VIN or engine serial number (ESN) before ordering.
Is this the same gasket as the front timing cover gasket?
No. Part number 3938156 seals the gear housing to the engine block. The steel front timing cover uses a separate gasket, such as the CUMMINS 3918673 front cover gasket on most 1994–2002 trucks. Many front-of-engine reseal jobs require both gaskets.
When should I replace the 3938156 timing gear housing gasket?
Replace this gasket any time the gear housing is removed—such as KDP repair, timing work, or swapping a damaged housing. The gasket is not designed to be reused, and reinstalling the old gasket can lead to persistent oil leaks and poor sealing.
Is this a genuine Cummins gasket or an aftermarket replacement?
This listing is for a genuine Cummins OEM 3938156 gasket supplied through CPP Diesel’s Cummins parts channel. Genuine Cummins parts ensure the correct material, thickness, and profile for long-term sealing performance on hard-working B-Series engines.
Do I need to use RTV or sealant with this gasket?
Follow the Cummins service manual for your specific engine. In most cases, the gasket is installed dry with only a thin film of approved sealant at specific joints and corners. Avoid coating the entire gasket in RTV, which can squeeze out and contaminate oil passages or gear teeth.
What other parts should I replace while I have the timing gear housing off?
This is the perfect time to perform a comprehensive front-of-engine refresh. CPP Diesel commonly recommends adding a CUMMINS 3937111 front crankshaft seal kit, the correct front cover gasket such as CUMMINS 3918673, and, where needed, a replacement gear housing like CUMMINS 3936256. Inspect the Killer Dowel Pin (KDP), dowel bores, and front main seal area while everything is apart for a long-lasting repair.
