Alternator

This procedure covers the removal and replacement of the alternator on a 1994-2007 Dodge Ram 2500 with the 5.9L Cummins I6 diesel engine and 4WD.

Warnings

Tools required

Parts

• Alternator × 1 — 120-130 amp (verify amperage for your specific year)
• Serpentine belt × 1 — Replace if worn, cracked, or contaminated

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine to cool completely
3. Open hood and secure with prop rod
4. Disconnect negative battery cable and isolate from battery post
5. Take photo of serpentine belt routing for reference

Procedure

1. 1

   Remove serpentine belt
   Locate the automatic belt tensioner on the front of the engine. Insert a 3/8" breaker bar or serpentine belt tool into the square hole on the tensioner pulley. Rotate the tensioner in the direction that relieves belt tension (verify direction for your specific setup) and slide the belt off the alternator pulley first, then remove from remaining pulleys. Slowly release tensioner back to resting position.
2. 2

   Disconnect alternator electrical connections
   Locate the alternator on the passenger side of the engine (verify location for your specific configuration). Remove the plastic protective boot from the B+ terminal (large stud with battery cable). Use appropriate socket to remove the nut securing the battery cable to the B+ terminal and remove cable. Disconnect the field wire connector by pressing the release tab and pulling straight out.
   ⚠Do not allow the B+ cable to contact ground or other metal components during removal
3. 3

   Remove upper alternator mounting bolt
   Locate the upper alternator mounting bolt that passes through the alternator mounting ear into the engine block. Remove this bolt completely using appropriate socket and extension. Note the position of any spacers or washers for reinstallation.
   Torque spec

   Alternator Mounting Bolts50 Nm (37 lb-ft)
4. 4

   Remove lower pivot bolt
   Locate the lower alternator mounting bolt at the bottom of the alternator mounting bracket. Remove this bolt completely. The alternator should now be free to be removed from the engine bay.
   Torque spec

   Alternator Pivot Bolt25 Nm (18 lb-ft)
5. 5

   Remove alternator from vehicle
   Carefully maneuver the alternator out of the engine bay. On 4WD models, you may need to angle the alternator to clear the front axle components. Take note of the orientation for reinstallation.
6. 6

   Prepare mounting surfaces and install new alternator
   Clean the alternator mounting surfaces on the engine block with a wire brush. Remove any corrosion or debris. Position the new or rebuilt alternator into the mounting bracket, ensuring it is oriented correctly. Insert the lower mounting bolt finger-tight first, then install the upper mounting bolt finger-tight.
7. 7

   Torque alternator mounting bolts
   Using a torque wrench, tighten the lower pivot bolt to specification first, then torque the upper mounting bolt. Ensure the alternator is properly seated in the mounting bracket before final torquing.
   Torque spec

   Alternator Pivot Bolt25 Nm (18 lb-ft)

   Alternator Mounting Bolts50 Nm (37 lb-ft)
8. 8

   Reconnect alternator electrical connections
   Reconnect the field wire connector to the alternator by pushing firmly until it clicks into place. Install the battery cable onto the B+ terminal stud and secure with the nut. Torque the battery terminal nut to specification. Reinstall the protective boot over the B+ terminal.
   ⚠Ensure field wire connector is fully seated and locked in place
   Torque spec

   Battery Terminal Bolts8 Nm (6 lb-ft)
9. 9

   Install serpentine belt
   Route the serpentine belt according to the diagram on the fan shroud or your reference photo. Install the belt on all pulleys except the alternator. Rotate the tensioner in the direction that relieves belt tension with your breaker bar and slip the belt onto the alternator pulley last. Ensure the belt is properly seated in all pulley grooves.
   ⚠Verify belt is properly seated on all pulleys before releasing tensioner to prevent belt damage or failure
10. 10

    Reconnect battery and test
    Reconnect the negative battery cable to the battery terminal and torque to specification. Start the engine and verify the alternator is charging by observing the battery warning light extinguishes and checking battery voltage with a multimeter (should read 13.8-14.5 volts with engine running).
    Torque spec

    Battery Terminal Bolts8 Nm (6 lb-ft)

Reassembly

1. Ensure all electrical connections are secure and properly routed away from moving components
2. Verify serpentine belt is properly aligned on all pulleys and has proper tension
3. Check that no tools or parts were left in the engine bay

Verification

• Start engine and verify battery warning light turns off within 2-3 seconds
• With engine running, measure voltage at battery terminals - should read 13.8-14.5 volts
• Turn on high electrical loads (headlights, HVAC blower, rear defroster) and verify voltage remains above 13.5 volts
• Listen for unusual noises from alternator or belt area
• Verify serpentine belt is tracking properly on all pulleys with engine running

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