Product Description
Genuine Cummins
Cummins 3937438 — Rocker Lever Adjusting Screw (Valve Lash Adjuster)
MPN: 3937438 | Also Known As: rocker arm adjuster screw, valve lash adjuster | Sold: Individually (12 per engine for a full set)
Why This Part
- ✓ OE ball-end geometry for precise valve lash and smooth rocker motion.
- ✓ Direct-fit for 5.9L 12-valve rocker levers (1989–1998).
- ✓ Hardened wear surfaces to reduce pitting and extend valvetrain life.
- ✓ Ideal when refreshing valvetrain, changing pushrods, or repairing lash issues.
OE Fit Stock Replacement 12 Per Engine
Quick Specs
| Type | Rocker lever adjusting screw (valve lash adjuster) |
|---|---|
| OE Part # | 3937438 |
| Qty Required | 12 per engine (sold individually) |
| Use Case | Restores correct valve lash; replace when ball-end is worn/pitted |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1989–1998 | 5.9L Cummins 6BT (12-Valve) | Dodge/Ram 2500 & 3500 |
Industrial/Off-Highway: Used primarily on Euro 2 5.9L B-series engines—verify by ESN before ordering.
Often Paired With
- Rocker Arms: Cummins 3910810 (exhaust), 3910811 (intake)
- Pushrods: Cummins 3284377 (commonly paired on 12-valve refreshes)
- Adjusting lock nut: replace any rounded/damaged nuts during lash service
What’s In The Box
- (1) Genuine Cummins Rocker Lever Adjusting Screw (3937438)
Install Tips
- Set valve lash to the factory specification from the Cummins service manual.
- Inspect rocker tips and pushrod cups; replace any worn components.
- Torque the lock nut to spec and recheck lash after initial warm-up.
FAQ
HOW MANY ADJUSTER SCREWS DO I NEED?There are 12 rocker levers on the 5.9L 12-valve—order 12 pieces for a complete set. This item is sold individually.
WILL THIS FIT 24-VALVE OR COMMON-RAIL ENGINES?This part targets the 5.9L 12-valve (1989–1998). Later VP44 24-valve and 2003+ common-rail engines use different rocker/adjuster designs.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3937438.
SHOULD I REPLACE PUSHRODS OR ROCKER ARMS AT THE SAME TIME?Inspect for wear. Many techs replace worn pushrods and any damaged rocker arms while resetting lash for best results.
DO I NEED ANY SPECIAL TOOLS?Basic hand tools and feeler gauges for lash. Follow Cummins’ lash procedure and torque specs.
Product Videos
Custom Field
Vehicle Year 1989,1990,1991,1992,1993,1994,1995,1996,1997,1998
Vehicle Make DODGE
ENGINE 5.9L
