CHUGGLE AT 35-45 MPH WITH TCC ENGAGED-REVISED PROM RELEASED

SUBJECT: CHUGGLE AT 35-45 MPH WITH THE TORQUE CONVERTER CLUTCH ENGAGED (REVISED CALIBRATION PROM) 1986-87 MODELS WITH 3.8L ENGINE

MODELS AFFECTED: 1986/87 CENTURY WITH 2.84 AXLE RATIO; 1986/87 LESABRE WITH 2.73 AXLE RATIO; 1986 PARK AVENUE WITH 2.84 AXLE RATIO; 1987 PARK AVENUE WITH 2.73 AXLE RATIO

Some owners of 1986 and 1987 Century, LeSabre, and Park Avenue models equipped with 3.8L (code B and 3) engine and standard axle ratio may experience a condition of chuggle at 35-45 MPH with the torque converter clutch engaged. If the condition cannot be repaired using currently published service and diagnostic procedures, it may be necessary to install a revised calibration prom.

The proms are currently available through GMSPO under the following numbers.

PROM PROM PROM TRANSAXLE AXLE SERVICE SCANNER BROADCAST YEAR SERIES RATIO PART NO. I.D. NO. CODE ----- ------- -------------- -------- ------- -------- 1986 Century F17/2.84 16158376 8394 AWWY (Fed. & Calif.)

1986 LeSabre FP3/2.73 16158375 8404 AWWZ (Fed. & Calif.)

1986 Electra F17/2.84 16158377 8384 AWWX (Non T-Type (Fed. & Calif.) models only)

1987 LeSabre/ FP3/2.73 16158373 8414 AWXA Electra (Fed. & Calif.)

1987 Century F17/2.84 16158372 8424 AWXB (Fed. & Calif.)

WARRANTY INFORMATION: Use applicable labor operation and time.

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.