chatter or vibration 42 to 45 mph in od on 1994 Dodge Ram 2500

when driving with no load

by in Rio Rancho, NM on April 04, 2011
1 answer
ANSWER by on April 07, 2011
There is a Technical Service Bulletin to address a similar issue. NO: 21-04-95 SUBJECT: Vibration or Perceived Engine Miss DATE: Apr. 14, 1995 NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH THE CUMMINS DIESEL ENGINE AND AUTOMATIC TRANSMISSION. SYMPTOM/CONDITION: A vibration or perceived engine miss at approximately 1100 RPM as the torque converter clutch engages. This condition occurs in 4th gear at speeds between 42 to 48 MPH. DIAGNOSIS: After duplicating the above condition, verify the part number on the Powertrain Control Module (PCM). For proper repair procedure, refer to the guidelines given below. If the vehicle is a 1994 MY equipped with PCM P/N 56027303 or 56027304, replace the PCM with P/N 4798745. Proceed to the PCM replacement section of this TSB. If the vehicle is a 1995 MY, verify that it is equipped with PCM P/N 56028335 or 56028336, and proceed to the PCM reprogramming section of this TSB. If the vehicle is equipped with a PCM other than 56028335, 56028336, 04798745, or 04856080, replace the PCM with P/N 4798745 and proceed to the PCM replacement section of this TSB. NOTE: IF THE VEHICLE IS EQUIPPED WITH PCM P/N 4798745 OR 4856080, THE SOFTWARE UPDATE NEEDED TO ADDRESS THIS TSB ISSUE HAS ALREADY BEEN COMPLETED AND NO FURTHER ACTION IS REQUIRED. PARTS REQUIRED: Quantity Part No. Description (1) 04798745 Module, Powertrain Control (1994 Only) (1) 4669020 Label - Authorized Software Update (1) 4275086 Label - Authorized Modification