This schedule is from the 1979 Dodge Diplomat/Magnum Owner's Manual.  See bottom of page for Severe Service schedule items.

Every 7,500 miles (12,000 km)
Apply solvent to carburetor choke shaft (or every six months)
Apply solvent to fast idle cam and pivot pin (or every six months)
Change engine oil (or every 12 months)
Replace engine oil filter (or every 12 months)
Check and adjust clutch pedal free play as required

Every 15,000 miles (24,000 km)
Apply solvent to carburetor choke shaft (or every six months)
Apply solvent to fast idle cam and pivot pin (or every six months)
Check and adjust idle speed and air-fuel mixture as required
Replace oxygen sensor
Check operation of positive crankcase vent valve, replace if necessary
Replace spark plugs (without catalytic converter)
Check and adjust tappet adjustment as required (six cylinder engines)
Inspect all fuel system & underhood rubber and plastic components (emissions hoses) and replace if necessary
Change engine oil (or every 12 months)
Check and service cooling system (or every 12 months)
Check condition and tension of drive belts
Check and adjust clutch pedal free play as required

Every 22,500 miles (36,000 km)
Apply solvent to carburetor choke shaft (or every six months)
Apply solvent to fast idle cam and pivot pin (or every six months)
Change engine oil (or every 12 months)
Replace engine oil filter (or every 12 months)
Check and adjust clutch pedal free play as required

Every 30,000 miles (48,000 km)
Check and adjust automatic choke as required
Apply solvent to carburetor choke shaft (or every six months)
Replace carburetor air filter
Clean crankcase inlet filter
Apply solvent to fast idle cam and pivot pin (or every six months)
Replace fuel filter
Check and adjust idle speed and air-fuel mixture as required
Apply solvent to manifold heat control valve
Replace oxygen sensor
Replace positive crankcase vent valve
Replace spark plugs (with or without catalytic converter)
Check and adjust tappet adjustment as required (six cylinder engines)
Inspect all fuel system & underhood rubber and plastic components (emissions hoses) and replace if necessary
Replace vapor storage canister filter element
Change engine oil (or every 12 months)
Check and service cooling system (or every 12 months)
Drain, flush and refill cooling system at 24 months, and every 12 months thereafter
Check condition and tension of drive belts
Inspect brake linings
Inspect front wheel bearings
Lubricate ball joints and tie rod ends
Check and adjust clutch pedal free play as required

Every 37,500 miles (60,000 km)
Apply solvent to carburetor choke shaft (or every six months)
Apply solvent to fast idle cam and pivot pin (or every six months)
Check operation of positive crankcase vent valve, replace if necessary
Change engine oil (or every 12 months)
Replace engine oil filter (or every 12 months)
Check and adjust clutch pedal free play as required

Every 45,000 miles (72,000 km)
Apply solvent to carburetor choke shaft (or every six months)
Apply solvent to fast idle cam and pivot pin (or every six months)
Check and adjust idle speed and air-fuel mixture as required
Replace oxygen sensor
Replace spark plugs (without catalytic converter)
Check and adjust tappet adjustment as required (six cylinder engines)
Inspect all fuel system & underhood rubber and plastic components (emissions hoses) and replace if necessary
Change engine oil (or every 12 months)
Check and service cooling system (or every 12 months)
Drain, flush and refill cooling system at 24 months, and every 12 months thereafter
Check condition and tension of drive belts
Check and adjust clutch pedal free play as required

SEVERE SCHEDULE
For trailer towing, taxi, police and limousine vehicles

Engine Oil
Change every 3 months or 3,000 miles (4,800 km)
Engine Oil Filter
Replace at initial oil change and r\every other oil change thereafter
Transmission Fluid
Change automatic every 15,000 miles (24,000 km), change filter, adjust bands
Change manual every 30,000 miles (48,000 km)
Axle Oil
Change every 36,000 miles (58,000 km)
Front Wheel Bearings
Inspect and lubricate every time drums or rotors are removed for service or inspection, and every 9,000 miles (14,000 km)
Brake Linings
Inspect every 9,000 miles (14,000 km)
Ball Joints and Tie Rod Ends
Lubricate every 18 months or 15,000 miles (24,000 km)
Universal Joints
Inspect at every oil change