A/T - Click or Whine in Third or Fourth Gear

Number: 93-228-7A
Section: 7A
Date: JUNE 1993
Corporate Bulletin No.: 277121R
ASE No.: A2

Subject:
CLICK/WHINE IN THIRD/FOURTH GEAR

Model and Year:
1988-93 CAPRICE, CAMARO AND CORVETTE
1988-93 C/K, RN, S/T, M AND G TRUCKS
1990-93 L VAN

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 92-157-7A, DATED APRIL 1992. THE 1993 MODEL YEAR HAS BEEN ADDED, AS WELL AS A NOTE IN THE CORRECTION SECTION. ALSO THE SERVICE PARTS INFORMATION HAS BEEN CHANGED. ALL COPIES OF 92-157-7A SHOULD BE DISCARDED.

CONDITION:
Some 1988-93 vehicles with HYDRA-MATIC 4L60 or 4L60-E transmissions built before November 19, 1992 (Julian Date 324) may exhibit a clicking or whining noise in third and fourth gear. A customer may also describe it as a ticking or rattle noise.

CAUSE:
The clicking noise is caused by transmission fluid passing over the friction plates of the low and reverse clutch. The fluid causes them to vibrate when the low and reverse clutch is not applied (third and fourth gear).

CORRECTION:
Install five new fiber plates in the low and reverse clutch. The new plates have a non-groove configuration.

NOTE:
All HYDRA-MATIC 4L60 and 4L60-E transmissions built on or after November 19,1992 (Julian Date 324) have been assembled with the new low and reverse clutch fiber plates.





SERVICE PARTS INFORMATION:

Parts are expected to be available on 6/07/93.