PROM - Low Speed Shudder or Vibration

91pontiac12

Bulletin Number: 92-6-8
Reference Number: 136506R
Publish Date: 10/91


Subject: SHUDDER OR VIBRATION AT LOW SPEEDS (INSTALL NEW PROM)


Models Affected: 1990 - 1992 TRANS SPORT WITH 3.1L


This bulletin has been revised to include the 1992 model year. This bulletin cancels and replaces bulletin 91-6-47 issued 8/91.

Condition:

Some owners of 1990 - 1992 Trans Sport models with 3.1L (VIN D) engine may comment of a Shudder or Vibration at low speeds.

Cause:

This condition may be caused by the transmission converter clutch being engaged at 23 MPH.

Correction:

If normal diagnostic procedures shown in your Service Manual (Section 6E2-B-3) do not correct this condition, a new PROM with a "TCC" ([1][2]torque converter clutch) engagement speed of 35 MPH is available. The part numbers are as follows:

1990 Vehicles

Emission PROM Scanner Broadcast
System Package No. I.D. Code

California 16163425 3431 AYAC

Federal 16163426 3441 AYAD


1991 And 1992 Vehicles

Emission PROM Scanner Broadcast
System Package No. I.D. Code

California 16164894 4911 AYHP

Federal 161648919 4901 AYHN

Note: This correction will have no impact on performance above 35 MPH.

Parts are currently available from GMSPO.

Labor Operation Number: T0500

Labor Time: .7 Hour