Product Description
The Cummins 4932378 OEM Connecting Rod Bearing (.040 Undersize / 1.00 mm) is a genuine, precision-machined undersize rod bearing designed for remanufactured or machined crankshafts on 1989–2002 5.9L Cummins B-Series engines. This bearing ensures proper oil clearance, correct crankshaft support, and OEM durability during high-load diesel operation. When restoring oil pressure or completing a full bottom-end rebuild, genuine Cummins bearings deliver the consistent metallurgy and reliability required for long-term engine life.
Undersize bearings like the .040” / 1.00 mm variant are used when crankshaft journals have been ground during machining. Installing OEM-spec bearings maintains factory tolerances and reduces wear, vibration, and bearing fatigue.
Fitment
- 1989–1998 Dodge Ram 2500/3500 with 5.9L 12-Valve Cummins (6BT)
- 1998.5–2002 Dodge Ram 2500/3500 with 5.9L 24-Valve ISB Cummins
- All 5.9L B-Series engines requiring .040 undersize (1.00 mm) connecting rod bearings
Note: Undersize bearings must match the machined crank journal size. Always confirm undersize requirements before installation.
Cross-Reference (Cummins-Only)
Related Cummins bottom-end components:
• Cummins 3903924 OEM Timing Pin – 12-Valve
• Cummins 3915787 OEM Threaded Plug – Oil System
• Cummins 3900267 Tappet Cover Bolt Grommet Seal
FAQ
What does .040 undersize / 1.00 mm mean?
It means the crankshaft rod journals have been machined .040” (1.00 mm) smaller, and these bearings restore correct oil clearance.
Can I install this bearing on a standard-size crankshaft?
No. Undersize bearings MUST match the crankshaft’s machined journal size. Standard-bearing engines require standard-size bearings.
Does this fit both 12-Valve and 24-Valve 5.9L Cummins engines?
Yes — this bearing fits 1989–2002 B-Series 5.9L engines, provided the crankshaft requires the .040 undersize specification.
Should rod bolts or other components be replaced during bearing service?
It is strongly recommended to inspect or replace rod bolts, rod bearings, main bearings, and oil pump during a bottom-end rebuild.
Specifications for cummins 4932378
| Specification | Value |
|---|---|
| Brand | Cummins Genuine Parts |
| Part Number | 4932378 |
| Bearing Size | .040 Undersize / 1.00 mm |
| Component Type | Connecting Rod Bearing |
| UPC | Not Published |
| GTIN | Not Published |
| Cross Reference | Used with machined crankshafts requiring 1.00 mm rod bearing undersize |
| E-Codes | N/A |
| Shipping Weight | 0.25 lbs per pair (approx.) |
| Package Dimensions | 3 x 3 x 2 in |
| Prop 65 Warning | Not Applicable |
