Peterbilt Engine Oil and Fluid Service Checklist

Comprehensive service procedures for engine oil and fluid maintenance across all Peterbilt truck models.

Fluid Service Overview

Proper fluid maintenance is critical for the performance, reliability, and longevity of Peterbilt trucks. This comprehensive checklist covers oil and fluid service procedures for all Peterbilt models, including the PACCAR MX engine family, Cummins engine options, and various transmission and axle configurations. Following these procedures and specifications will help maximize component life, reduce downtime, and maintain optimal efficiency across all vehicle systems. Regular fluid service is one of the most cost-effective preventive maintenance practices for protecting your Peterbilt investment.

Engine Oil Service Procedures

Follow these procedures for proper engine oil service based on engine type.

PACCAR MX-13 Engine Oil Service

  • Warm engine to operating temperature
  • Position vehicle on level surface
  • Remove oil fill cap to aid drainage
  • Locate and remove oil drain plug
  • Allow oil to drain completely (minimum 15 minutes)
  • Replace drain plug with new gasket
  • Remove and replace oil filter(s)
  • Fill with 42 quarts (39.7L) of approved oil
  • Verify oil level on dipstick after filling
  • Run engine and check for leaks
  • Recheck oil level after shutdown
  • Reset oil change interval monitor

PACCAR MX-11 Engine Oil Service

  • Warm engine to operating temperature
  • Position vehicle on level surface
  • Remove oil fill cap to aid drainage
  • Locate and remove oil drain plug
  • Allow oil to drain completely (minimum 15 minutes)
  • Replace drain plug with new gasket
  • Remove and replace oil filter(s)
  • Fill with 38 quarts (36L) of approved oil
  • Verify oil level on dipstick after filling
  • Run engine and check for leaks
  • Recheck oil level after shutdown
  • Reset oil change interval monitor

Cummins X15 Engine Oil Service

  • Warm engine to operating temperature
  • Position vehicle on level surface
  • Remove oil fill cap to aid drainage
  • Locate and remove oil drain plug
  • Allow oil to drain completely (minimum 15 minutes)
  • Replace drain plug with new gasket
  • Remove and replace oil filter(s)
  • Fill with 44 quarts (41.6L) of approved oil
  • Verify oil level on dipstick after filling
  • Run engine and check for leaks
  • Recheck oil level after shutdown
  • Reset oil change interval monitor

PACCAR PX-9 Engine Oil Service

  • Warm engine to operating temperature
  • Position vehicle on level surface
  • Remove oil fill cap to aid drainage
  • Locate and remove oil drain plug
  • Allow oil to drain completely (minimum 15 minutes)
  • Replace drain plug with new gasket
  • Remove and replace oil filter
  • Fill with 22 quarts (20.8L) of approved oil
  • Verify oil level on dipstick after filling
  • Run engine and check for leaks
  • Recheck oil level after shutdown
  • Reset oil change interval monitor

Transmission Fluid Service

Follow these procedures for transmission fluid service based on transmission type.

PACCAR TX-18 Manual Transmission

  • Position vehicle on level surface
  • Locate fill and drain plugs
  • Remove fill plug first to ensure drainage
  • Remove drain plug and drain fluid
  • Allow complete drainage (minimum 15 minutes)
  • Install drain plug with new gasket
  • Fill with 16 pints (7.6L) of approved fluid
  • Fill until fluid reaches bottom of fill hole
  • Install fill plug with new gasket
  • Check for leaks after first operation
  • Inspect for proper shift operation

Eaton Fuller Manual Transmission

  • Position vehicle on level surface
  • Locate fill and drain plugs
  • Remove fill plug first to ensure drainage
  • Remove drain plug and drain fluid
  • Allow complete drainage (minimum 15 minutes)
  • Install drain plug with new gasket
  • Fill with specified amount of approved fluid
  • Fill until fluid reaches bottom of fill hole
  • Install fill plug with new gasket
  • Check for leaks after first operation
  • Inspect for proper shift operation

Allison Automatic Transmission

  • Warm transmission to operating temperature
  • Position vehicle on level surface
  • Locate and remove oil pan bolts
  • Carefully lower pan to avoid spills
  • Replace filter and gasket
  • Clean pan and magnet
  • Reinstall pan with new gasket
  • Torque bolts to specification
  • Add approximately 7 quarts (6.6L) of TES-295 fluid
  • Start engine and check fluid level
  • Fill to proper level on dipstick
  • Check for leaks and proper operation

PACCAR/Eaton Automated Transmission

  • Position vehicle on level surface
  • Locate fill and drain plugs
  • Remove fill plug first
  • Remove drain plug and drain fluid
  • Allow complete drainage (minimum 15 minutes)
  • Install drain plug with new gasket
  • Fill with specified amount of synthetic fluid
  • Fill until fluid reaches bottom of fill hole
  • Install fill plug with new gasket
  • Check for leaks after first operation
  • Verify proper shift operation

Axle and Differential Service

Follow these procedures for axle and differential fluid service.

Front Axle Service

  • Position vehicle on level surface
  • Locate fill and drain plugs
  • Remove fill plug first
  • Remove drain plug and drain fluid
  • Allow complete drainage (15-20 minutes)
  • Install drain plug with new gasket
  • Fill with specified gear oil
  • Fill until fluid reaches bottom of fill hole
  • Install fill plug with new gasket
  • Clean excess fluid and check for leaks
  • Test drive and recheck for leaks

Rear Axle/Differential Service

  • Position vehicle on level surface
  • Locate fill and drain plugs
  • Remove fill plug first
  • Remove drain plug and drain fluid
  • Allow complete drainage (15-20 minutes)
  • Install drain plug with new gasket
  • Fill with specified gear oil
  • Fill until fluid reaches bottom of fill hole
  • Install fill plug with new gasket
  • Clean excess fluid and check for leaks
  • Test drive and recheck for leaks

Tandem Axle Service

  • Position vehicle on level surface
  • Locate all fill and drain plugs
  • Remove all fill plugs first
  • Remove forward rear axle drain plug
  • Remove rear rear axle drain plug
  • Allow complete drainage (15-20 minutes)
  • Install drain plugs with new gaskets
  • Fill each differential to proper level
  • Fill power divider (forward axle)
  • Install all fill plugs with new gaskets
  • Clean excess fluid and check for leaks

Wheel End/Hub Oil Service

  • Position vehicle on level surface
  • Locate hub cap or fill plug
  • Remove hub cap or fill plug
  • Drain old oil completely
  • Inspect hub seal for leaks
  • Check bearings if accessible
  • Fill hub with specified oil
  • Fill to proper level mark on hub cap
  • Reinstall hub cap or fill plug
  • Clean excess fluid
  • Check for leaks after operation

Cooling System Service

Follow these procedures for cooling system service and maintenance.

Coolant Level Check

  • Ensure engine is cold
  • Check coolant level in surge tank
  • Verify level is between min/max marks
  • Inspect coolant color and condition
  • Check for contamination or debris
  • Test coolant freeze protection
  • Verify coolant concentration (40-60%)
  • Check coolant pH level (7.5-11)
  • Inspect surge tank cap for damage
  • Check cooling system pressure
  • Verify no signs of leaks or seepage

Coolant Filter Service

  • Locate coolant filter housing
  • Position drain pan under filter
  • Close coolant filter shut-off valve (if equipped)
  • Remove filter housing cover
  • Remove and discard old filter element
  • Clean filter housing interior
  • Install new filter element
  • Verify O-ring is in good condition
  • Reinstall housing cover
  • Open shut-off valve
  • Check coolant level and add if necessary

Complete Coolant Exchange

  • Ensure engine is cool
  • Remove radiator cap
  • Open radiator drain valve
  • Open engine block drain
  • Drain all coolant completely
  • Flush system with clean water if needed
  • Close all drain valves
  • Replace coolant filter
  • Fill system with premixed coolant
  • Verify proper coolant level
  • Run engine to operating temperature
  • Check for leaks and proper level after cooling

Coolant Analysis

  • Obtain proper sample container
  • Ensure engine is warm but not hot
  • Draw coolant sample from radiator or petcock
  • Label sample with vehicle information
  • Test freeze protection with refractometer
  • Check pH level with test strips
  • Test SCA (Supplemental Coolant Additive) level
  • Look for signs of oil contamination
  • Check for suspended particles
  • Send sample for lab analysis if needed
  • Document results in maintenance records

Specialized Fluid Service

Follow these procedures for other critical fluid systems in Peterbilt trucks.

Power Steering Fluid Service

  • Position vehicle on level surface
  • Locate power steering reservoir
  • Check fluid level on dipstick/sight glass
  • Inspect fluid color and condition
  • If service needed, locate and remove drain plug
  • Drain fluid completely
  • Refill with approved ATF fluid
  • Start engine and turn steering lock-to-lock
  • Recheck fluid level and top off as needed
  • Inspect for leaks and proper operation
  • Verify proper fluid level when warm

Diesel Exhaust Fluid (DEF) Service

  • Check DEF level on dash gauge
  • Ensure DEF is clear with no discoloration
  • Use only API-certified DEF fluid
  • Verify DEF concentration (32.5%)
  • Keep DEF tank at least 1/4 full
  • Inspect DEF tank fill cap for proper sealing
  • Check for crystallization around connections
  • Clean filler neck before adding DEF
  • Never add anything but DEF to tank
  • Protect from contamination during filling
  • Verify proper DEF quality via dash indicators

Hydraulic System Fluid Service

  • Position vehicle on level surface
  • Locate hydraulic reservoir
  • Check fluid level in sight glass
  • If service needed, release system pressure
  • Remove reservoir drain plug
  • Drain hydraulic fluid completely
  • Replace hydraulic filters
  • Install drain plug with new seal
  • Fill with approved hydraulic fluid
  • Start system and cycle all functions
  • Check for leaks and proper operation
  • Verify final fluid level after cycling

Air System Service

  • Drain all air tanks completely
  • Check air dryer operation
  • Inspect air dryer purge valve
  • If equipped with alcohol evaporator, refill
  • Check for air system leaks
  • Verify proper governor cut-in/cut-out
  • Test low air warning devices
  • Replace air dryer desiccant cartridge per schedule
  • Inspect air lines for chafing or damage
  • Check air system pressure build-up time
  • Verify proper brake application and release

Fluid Analysis Program

Implement these fluid analysis procedures to maximize component life.

Engine Oil Analysis

  • Take sample at normal operating temperature
  • Use vacuum pump with clean tubing
  • Draw sample from dipstick tube or sampling valve
  • Fill sample bottle 3/4 full
  • Label with complete vehicle information
  • Include hours/miles since last oil change
  • Send to laboratory for analysis
  • Review for abnormal wear metals
  • Check for coolant or fuel contamination
  • Verify viscosity is within range
  • Track trend data over time
  • Adjust service intervals based on results

Transmission Fluid Analysis

  • Take sample at normal operating temperature
  • Obtain sample from fill plug or dipstick tube
  • Use clean sampling equipment
  • Fill sample bottle 3/4 full
  • Label with complete vehicle information
  • Include hours/miles since last service
  • Send to laboratory for analysis
  • Review for abnormal wear metals
  • Check for contamination
  • Verify viscosity is within range
  • Look for oxidation indicators
  • Adjust service intervals based on results

Coolant Analysis

  • Take sample when coolant is warm
  • Draw from radiator or petcock
  • Fill sample bottle 3/4 full
  • Label with complete vehicle information
  • Include coolant type and service date
  • Send to laboratory for analysis
  • Check pH level (should be 7.5-11)
  • Verify freeze point protection
  • Check for proper SCA levels
  • Look for contaminants or corrosion
  • Verify nitrite and molybdate levels
  • Implement corrective actions as needed

Differential Fluid Analysis

  • Take sample at normal operating temperature
  • Obtain sample from fill plug
  • Use clean sampling equipment
  • Fill sample bottle 3/4 full
  • Label with complete vehicle information
  • Include hours/miles since last service
  • Send to laboratory for analysis
  • Review for abnormal wear metals
  • Check for water contamination
  • Verify viscosity is within range
  • Look for oxidation indicators
  • Adjust service intervals based on results
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