Riviera V6-3.8L SC VIN 1 (1995)
PROM - Programmable Read Only Memory: Customer Interest
Driveline - Vibration Over 37 MPH
File In Section: 6E - Engine Fuel & Emission
Bulletin No.: 53-65-06A
Date: June, 1997
Subject:
Driveline Vibration Over 37 mph (Replace PROM)
Models:
1994-95
Buick LeSabre, Park Avenue, Ultra
1995
Buick Riviera
1994-95
Oldsmobile Eighty Eight, Ninety Eight
1994-95
Pontiac Bonneville
with 3.8L 3800 Engine (VINs L, K, 1 - RPOs L27, L36, L67)
This bulletin is being revised to include vehicles with supercharged (L67) engines. Please discard Corporate Bulletin Number 53-65-06
(Section 6E - Engine Fuel & Emission).
Condition
Some owners may comment on a condition described as a "vibration", "miss", "chuggle", "hesitation", or "fishbite" sensation while driving the vehicle at
37 mph or higher.
Cause
With the Torque Converter Clutch (TCC) engaged, any powertrain or vehicle rotating disturbance is transmitted to the passenger compartment.
Important:
Verify concern with owner before proceeding with correction.
Correction
Determine that the following conditions do not exist before proceeding:
1.
Out-of-balance tires
2.
Out-of round tires
3.
Engine miss due to ignition related components or an inoperative mechanical function
4.
A/C compressor cycling
5.
TCC malfunctions causing excessive slip values as measured with a scan tool; or
6.
Specific road conditions
If it is determined that the above conditions are not present and no other conditions are causing the concern as outlined in Section 6E3-B in the
appropriate Service Manual, replace PROM (refer to ATTACHMENT 1). FOR SUPERCHARGED L67 ENGINES, CONTACT TECHNICAL
ASSISTANCE.
This PROM will only raise the third gear TCC lock from 37 to 50 mph and fourth gear TCC lock from 45 to 54 mph for vehicles equipped with VIN "L"
and "K" only. Refer to Section 6E3-C1 in the appropriate Service Manual for PROM replacement procedures.
Important:
No other driveability issues are addressed with this PROM.
VERIFY THE CONCERN IS NO LONGER OCCURRING BEFORE RETURNING THE VEHICLE TO THE OWNER.
Note 1
The revised PROMS are not considered a 100% cure; however, most owners do not perceive the "chuggle" or "fishbite" sensation with the higher
TCC lock up speeds.
