For 1990-2009 cars

# DIESEL CRUISEMASTER/SURGE IMPROVED PERFORMANCE

THE FOLLOWING REVISED SERVO APPLICATION INFORMATION APPLIES TO 1982 5.7L DIESEL VEHICLES EXHIBITING CRUISE INSTABILITY, HUNTING OR SURGING CONDITIONS.

THREE SPEED AUTOMATIC TRANSMISSION: REPLACE THE 1982 SERVO (GREY SERVO COVER WITH FOUR LB. RETURN SPRING) WITH THE 1981 OE SERVO (BLACK COVER WITH NINE LB. RETURN SPRING). THE SERVICE PACKAGE FOR THE 1981 SERVO WITH BLACK COVER IS 25030980.

FOUR SPEED AUTOMATIC TRANSMISSION: REPLACE THE OE EARLY PRODUCTION SERVO (SERVO PACKAGE 25031615) WITH THE NEW SERVICE REPLACEMENT SERVO PACKAGE 25031726. 1.OE EARLY PRODUCTION HAS A FOUR LB. RETURN SPRING WHILE THE NEW SERVICE REPLACEMENT SERVO PACKAGE HAS A SIX LB. RETURN SPRING. 2.THE REPLACEMENT SERVICE SERVO IN PACKAGE 25031726 IS CODED AE. 3.BOTH SERVOS HAVE GREY COVERS.

#### SUBJECT: CRUISEMASTER DIESEL TRANSDUCER AND SERVO USAGE

#### VEHICLES AFFECTED: 1982 VEHICLES EQUIPPED WITH DIESEL ENGINES AND CRUISE CONTROL

NEW TRANSDUCERS ARE RELEASED FOR 1982 AS LISTED BELOW:

APPLICATION: TRANSDUCER/VALVE ASSEMBLY: CHEVROLET 25031603 (TWO TERMINAL) BUICK 25031604 (THREE TERMINAL) PONTIAC 25031683(TWO TERMINAL) OLDSMOBILE 25031683 (TWO TERMINAL) CHEV. TRUCK 6.2L ENGINE 25031592(TWO TERMINAL)

THESE TRANSDUCERS INCORPORATE A NEW ORIFICE TUBE AND VALVE ASSEMBLY. TRANSDUCERS WITH THE NEW ORIFICE TUBE AND VALVE ASSEMBLY ARE IDENTIFIED BY A "BLACK" TRANSDUCER SOLENOID HOUSING. SOME 1982 5.7L DIESEL ENGINES EQUIPPED WITH THREE SPEED TRANSMISSIONS MAY EXHIBIT CRUISE INSTABILITY, HUNTING, OR SURGING. ON THESE VEHICLES, REPLACE THE 1982 ORIGINAL EQUIPMENT SERVO (GREY SERVO COVER WITH NO. 4 RETURN SPRING) WITH THE 1981 ORIGINAL EQUIPMENT SERVO, PART NUMBER 25031615 (BLACK SERVO COVER WITH NO. 9 RETURN SPRING).

THE PART NUMBERS FOR 1981 USAGES ARE LISTED BELOW: APPLICATION: TRANSDUCER/VALVE ASSY. CHEV-PONT-OLDS DIESEL 25030880 (TWO TERMINAL) BUICK DIESEL 25030877 (THREE TERMINAL)

RESUME VALVE CONNECTOR COVER BREAKAGE CAN OCCUR ON 1981-82 VEHICLES DURING HARNESS DISCONNECTION OR IN TRANSIT. CORRECTIVE ENGINEERING CHANGES HAVE BEEN MADE TO THE LOCKING TAB STOP. COVER REPLACEMENT CAN BE MADE INSTEAD OF COMPLETE RESUME VALVE REPLACEMENT BY UTILIZING SERVICE PART NUMBER 1984405 AVAILABLE FROM GM PARTS. THE SERVICE PACKAGE CONSISTS OF A NEW COVER, FILTER, AND INSTRUCTION SHEET.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.