Regal V6-231 3.8L Turbo VIN 8 4-bbl (1983)
Torque Converter Clutch: Customer Interest
A/T - Early TCC Engagement
Model Year 1983
Bulletin No. 83-32A
File in Group 70
Number 1A
Date May '83
SUBJECT:
Early TCC Engagement - All Vehicles Using An ECM Controlled TCC
NOTICE:
This Bulletin supersedes Bulletin 83-32, File Group 70, Number 1, dated Dec. 1982, to include updated information. Please discard
original Bulletin and replace with new Bulletin 83-32A.
Buicks exhibiting an early TCC engagement causing a stumbling or detonating condition may be due to grease or dirt on the two (2) reflective bars of the
speedometer head that serve as reflective panels for the VSS signal. Any foreign material on these bars will interfere with their reflective properties,
thereby generating a false (higher) vehicle speed signal to the ECM.
Dealers equipped with an ALCL tool can quickly check this by comparing speedometer reading to MPH reading the ECM is receiving. If the reading on
the ALCL tool is much higher than the speedometer reading, this is usually a good indication that the reflective surfaces have foreign material interfering
with their reflective properties.
The reflective bars should be thoroughly cleaned if this condition is found.
All other normal diagnostic procedures should be followed before suspecting this condition.
