Cummins ISB 6.7L, 5.9L, 4.5L Engine Rebuild Kit, New (ISB631076)

Fully Overhaul Your Cummins ISB 6.7L, 5.9L, or 4.5L with the ISB631076 Rebuild Kit

Is your Cummins ISB 6.7L, 5.9L, or 4.5L burning oil, losing compression, or knocking on startup? When an ISB reaches the point where a full overhaul is the right call, the quality of the parts going back in determines how long the engine runs before it needs attention again. Some OE rebuild kits get filled out with reconditioned or take off components to hold the price down. 4BTdiesel’s ISB631076 overhaul kit uses all new parts, manufactured to OEM specifications and tolerances in an ISO 9001 certified facility, so your rebuild starts with components you can count on across every cylinder, bearing journal, and seal surface on the engine.

Full Overhaul Kit vs. Inframe Kit: What’s the Difference?

This is a full overhaul kit, not just an inframe kit. The distinction matters because an overhaul kit is designed to cover every major wear surface on the engine, top and bottom, rather than only the cylinder and bearing components an inframe job addresses. The ISB631076 covers six standard piston kits, a complete lower gasket kit, a complete upper gasket kit, rod and main bearing sets, a front crankshaft seal, and a thermostat kit, giving you everything needed to fully renew the ISB from the pan gasket up through the valve cover and cylinder head.

What’s Included in the ISB631076 Overhaul Rebuild Kit

Piston Kits with High Performance Piston Pins

Each of the six piston kits, part number 4955365, pairs a new standard piston with a high performance piston pin, two piston pin retainers, and a piston ring set, restoring compression and oil control across every cylinder.

Complete Lower and Upper Gasket Kits

The lower gasket kit, part number 4955522, covers the front and rear crankshaft seals with installation tooling, both oil pan gaskets, the gear housing gasket, oil pickup gaskets, the rear cover gasket, and all related O-rings and sealing rings for the bottom of the engine. The upper gasket kit, part number 4955523, covers the cylinder head gasket, both valve cover gaskets, the rocker housing gasket, 24 valve stem seals, six injector seals, 26 fuel fitting seals, four EGR valve gaskets, six exhaust manifold gaskets, the intake manifold cover gasket, accessory drive gasket, thermostat seal, fuel pump gasket, and a full range of O-rings used throughout the top end. A capscrew length gauge and engine break-in documentation round out the kit.

Rod Bearing Kits, Main Bearing Kit, and Thermostat Kit

Six rod bearing kits pair a rod bearing and lower bearing for each cylinder. The main bearing kit, part number 3802070, includes six upper main bearings, seven main bearings, and a thrust bearing, giving the crankshaft new wear surfaces on every journal. A thermostat kit, part number 3954830, rounds out the package with a new thermostat and thermostat seal.

Fitment Information for the Cummins ISB Overhaul Kit (ISB631076)

The ISB631076 fits the Cummins ISB 6.7L, ISB 5.9L, and ISB 4.5L diesel engine family and cross references to part numbers 5633411, ISB631-076, M-5633411, M5633411, PAICUPISB631-076, and PAICUPISB631076. Rod and main bearing sizes must be selected at checkout, Standard, .010, .020, .025, .030, or .050, to match your crankshaft’s current dimensions. 4BTdiesel also asks for your engine serial number or VIN so the parts team can verify fit before the kit ships.

Get Your New Cummins ISB Overhaul Rebuild Kit (ISB631076) from 4BTdiesel

Every ISB631076 kit ships with zero core charge and a 6-month warranty, with professionally certified factory mechanic support from order through installation. In stock orders placed by 2 PM EST ship the same day, Monday through Friday. A complete set of all new components, zero core charge, and a warranty that covers the full overhaul make this kit a dependable way to bring your Cummins ISB 6.7L, 5.9L, or 4.5L back to factory condition.

Frequently Asked Questions About Cummins ISB Overhaul Rebuild Kit (ISB631076)

What does the ISB631076 overhaul rebuild kit include?

The kit includes six piston kits with high performance piston pins and ring sets, a complete lower gasket kit with front and rear crankshaft seals and installation tooling, a complete upper gasket kit with the cylinder head gasket, valve cover gaskets, valve stem seals, injector seals, fuel fitting seals, EGR and exhaust manifold gaskets, a capscrew length gauge, rod and main bearing kits, a thermostat kit, and engine break-in documentation.

What is the difference between an overhaul kit and an inframe kit?

An inframe kit covers the cylinder liners, pistons, and bearings needed to renew the bore and lower end without removing the engine from the frame. An overhaul kit goes further by also including complete upper and lower gasket sets, crankshaft seals, and other components needed to fully renew the engine from the oil pan up through the valve cover and cylinder head.

Which Cummins ISB engines does this kit fit?

This kit fits the Cummins ISB 6.7L, ISB 5.9L, and ISB 4.5L diesel engine family. It cross references to part numbers 5633411, ISB631-076, M-5633411, M5633411, PAICUPISB631-076, and PAICUPISB631076.

How do I know which bearing size to order?

Rod and main bearings are machined to specific oversizes that correspond to how far your crankshaft journals have been turned down during prior service. Select Standard, .010, .020, .025, .030, or .050 at checkout based on your engine’s current measurements, and submit your engine serial number or VIN so 4BTdiesel can confirm fit before the kit ships.

Why does the piston kit include a high performance piston pin?

The high performance piston pin, part number 4931041, is a heavier duty version of the standard pin that offers improved durability under the stress of normal ISB operating cycles. It is included in the kit as a direct upgrade over the standard pin without any additional cost or special installation requirement.

Does this overhaul kit include a core charge?

No. The ISB631076 overhaul rebuild kit ships with zero core charge, so there is no deposit to pay and nothing to return after the rebuild.

Warranty

6-month warranty.

How fast will my rebuild kit ship?

In stock orders placed by 2 PM EST ship the same day, Monday through Friday, so your shop can keep the overhaul on schedule.

What Rebuild Kit and Gasket Set Includes