RAM 1500 Truck 2WD V6-3.9L VIN X (1999)
Crankshaft: Service and Repair
Service Procedures
Fitting Bearings
Bearing caps are NOT interchangeable and should be marked at removal to ensure correct assembly. Upper and lower bearing halves are NOT
interchangeable. Lower main bearing halves of No. 1 and 3 are interchangeable.
Main Bearing Identification
Upper and lower No. 2 bearing halves are flanged to carry the crankshaft thrust loads. They are NOT interchangeable with any other bearing halves in
the engine. Bearing shells are available in standard and the following undersizes: 0.25 mm (0.001 inch), 0.051 mm (0.002 inch), 0.076 mm (0.003
inch), 0.2,54 mm (0.010 inch) and 0.305 mm (0.012 inch). Never install an undersize bearing that will reduce clearance below specifications.
Journal Inspection
Location Of Crankshaft Identification
A crankshaft that has undersize journals is stamped with 1/4 inch letters near the notch of the No. 6 crankshaft counterweight.
FOR EXAMPLE: R2 stamped on the No. 6 crankshaft counterweight indicates that the No.2 rod journal is 0.025 mm (0.001 inch) undersize. M4
indicates that the No. 4 main journal is 0.025 mm (0.001 inch) undersize. R3 M2 indicates that the No. 3 rod journal and the No. 2 main journal are
both 0.025 mm (0.001 inch) undersize.
When a crankshaft is replaced, all main and connecting rod bearings, should be replaced with new bearings. Therefore, selective fitting of the bearings
is not required when a crankshaft and bearings are replaced.
