Product Description
Cummins 4089263 — Upper Engine Gasket Set (ISB 5.9L, Rear Gear)
MPN: 4089263 | Also Known As: upper gasket kit, top-end gasket set | Application: HPCR ISB 5.9 (rear gear/EGR variants)
Why This Part
- ✓ OE kit for resealing the cylinder head/top-end on ISB 5.9L.
- ✓ Direct-fit for 2003–2007 Ram 5.9L common-rail (verify rear gear by VIN/ESN).
- ✓ Comprehensive sealing to prevent oil/coolant leaks post-rebuild.
- ✓ Genuine Cummins materials for durability under heat and vibration.
Quick Specs
| Type | Upper Engine Gasket Set (Top-End) |
|---|---|
| OE Part # | 4089263 |
| Kit Notes | HPCR with Rear Gear/EGR configurations; contents vary by ESN |
| Qty Required | 1 kit per engine |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 2003–2007 | Ram 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
Industrial/Off-Highway: Used primarily on EPA02 ISB/QSB 5.9 applications; always verify by ESN to match kit contents.
Often Paired With
- Lower Engine Gasket Kit: Cummins 4089173 (ISB 5.9, 2003–2007)
- Head Fasteners: ARP 247-4202 head stud kit or OE head bolts
- Fresh fluids & filters after reassembly and heat cycle
What’s In The Box
- (1) Genuine Cummins Upper Engine Gasket Set (4089263)
- Kit contents (gaskets, seals, o-rings) vary by ESN / configuration
Install Tips
- Clean mating surfaces, chase threads, and torque fasteners to spec.
- Confirm head gasket selection by ESN and service manual notes.
- Recheck for leaks after the first heat cycle.
FAQ
WILL THIS FIT MY 2003–2007 5.9L CUMMINS RAM?Yes—4089263 targets 2003–2007 5.9L ISB common-rail trucks. Verify ESN for rear-gear/EGR configuration to ensure the correct kit.
IS THIS THE “REAR GEAR” (RGT) UPPER KIT?Yes—4089263 is commonly referenced for HPCR with rear gear/EGR setups. Always confirm by ESN to match hardware and gasket styles.
WHAT’S INCLUDED IN THE KIT?Typical contents include the cylinder head gasket, valve cover/rocker housing gaskets, intake & exhaust manifold gaskets, injector seals, turbo & thermostat seals, and multiple o-rings/washers. Exact contents can vary by ESN.
DO I ALSO NEED THE LOWER GASKET KIT?If the bottom end is opened, pair this with the lower kit (commonly 4089173). For top-end service only, the upper kit is typically sufficient.
IS THIS A GENUINE CUMMINS PART?Yes—4089263 is a genuine Cummins kit for OE fit, materials, and durability.
