Speed Control - Surge at highway Speeds

NO.:
08-07-93 Rev. A

GROUP:
Electrical

DATE:
Mar. 19, 1993



SUBJECT:
Speed Control Surge



NOTE:
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 08-07-93 WHICH SHOULD BE REMOVED FROM YOUR FILES. ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS**.

NOTE:
THIS BULLETIN APPLIES ONLY TO FOUR WHEEL DRIVE VEHICLES EQUIPPED WITH THE CUMMINS DIESEL ENGINE.


MODELS:

1992-93 (AD) Ram Pickup/Ram Cab Chassis


SYMPTOM/CONDITION:

Some vehicles may exhibit a speed variation at highway speeds while the speed control is engaged.


DIAGNOSIS:

1. Perform the speed control system test as outlined in Section 8H of the service manual. If no problems are found during the test, proceed to step 2.

2. On 1992 vehicles verify that the vehicle is equipped with the correct speed control servo and cable for the Powertrain Control Module (SBEC) that is installed, Refer to the chart below and make sure that the Powertrain Control Module, servo and cable match.


POWERTRAIN CONTROL MODULE REFERENCE CHART


SBEC Part No. Servo Part No. Cable Part No.

56027570 53007954 (Zemco) **4428787**
56027571 53007954 (Zemco) **4428787**
56027572 53007954 (Zemco) **4428787**
96027573 53007954 (Zemco) **4428787**


POWERTRAIN CONTROL MODULE REFERENCE CHART CONT'D



SBEC Part No. Servo Part No. Cable Part No.

56027081 53009315 (Eaton) **52078330**
56028082 53009315 (Eaton) **52078330**
56027083 53009315 (Eaton) **52078330**
56027084 53009315 (Eaton) **52078330**


3. If no problems have been found to this point, the speedometer drive gear on the output shaft of the NP 205 transfer case may be at fault. Remove the speed sensor, adapter and the speedometer drive gear. Carefully inspect the speedometer drive gear while rotating the output shaft. Any cuts or irregularities on the gear can cause a speed sensor signal variation. If any irregularities are present, proceed to the repair procedure.


PARTS REQUIRED:

1 Speedometer Drive Gear 3732038


REPAIR PROCEDURE:

Replace the speedometer drive gear using the procedures outlined in Section 21 of the Rear Wheel Drive Dodge Truck Service Manual.


POLICY:
Reimbursable within the provisions of the warranty.


TIME ALLOWANCE:
Labor Operation No. 21-97-10-91................................0.6 Hrs.


FAILURE CODE:
58 - Internal Defect