A/T - Harsh Gear Shift/Harsh/Delayed Engagement
File In Section: 7 - TransmissionBulletin No.: 87-71-65
Date: June, 1998
Subject:
Harsh Garage Shift, Harsh or Delayed Engagement of Park to Reverse or Drive to Reverse (Install SRTA and Reflash Calibration)
Models:
1998 Cadillac DeVille, Eldorado, Seville
1998 Oldsmobile Aurora
Built Prior to February 16, 1998 with HYDRA-MATIC 4T80-E Transaxle (RPO MH1) and 4.0L, 4.6L Engine (VINs C, Y, 9 - RPOs L47, LD8, L37)
Condition
(See Figure 1)
Some customers of vehicles equipped with the above transaxles built prior to February 16, 1998 (Julian Date 047) may comment on a harsh garage shift, sometimes described as a delayed or harsh engagement from park to reverse or drive to reverse. The customer may also describe this as a metallic "clunk" noise at the end of the shift.
Cause
This condition may be due to a combination of reverse clutch configuration, accumulation and vehicle calibration of this shift maneuver.
Original Model Code Before February 16, 1998
8AAN 4.6L (LD8) E/K/K-Spec
8ABN 4.6L (LD8) E/K/K-Spec
8ADN 4.6L (L37) E/K/K-Spec
8AJN 4.6L (L37) E/K Car Export
8ACN 4.6L (L37) E/K Car Export
8MLN 4.6L (L37) E/K/K-Spec
8MDN 4.0L (L47) G Car
8MSN 4.0L (L47) G Car
Service Information (See Figures 2 and 3)
Individual service component parts will be available for both the original 1998 model code transaxles and the garage shift updated model code transaxles. Parts cataloging will reference the February 16, 1998 (Julian Date 047) breakpoint. Refer to Figures 2 and 3 for definition of individual component changes. Intermixing of individual components will cause premature transaxle failure.
Correction
Transaxle assembly plants started producing transaxles that contain an enhanced garage shift package on February 16, 1998 (Julian Date 047), to improve the park to reverse garage shift feel. New model codes were introduced to help track the implementation of this change. In order to correct this condition on a customer's vehicle with a transaxle built prior to February 16, 1998 (Julian Date 047), it will be necessary to install a Goodwrench SRTA with the new model code, and reflash the calibration in the PCM.
Updated Model Code Starting February 16, 1998
8BBN 4.6L (LD8) E/K/K-Spec
8BSN 4.6L (LD8) E/K/K-Spec
8CLN 4.6L (L37) E/K/K-Spec
8CMN 4.6L (L37) E/K Car Export
8CRN 4.6L (L37) E/K Car Export
8CTN 4.6L (L37) E/K/K-Spec
8DCN 4.0L (L47) G Car
8DFN 4.0L (L47) G Car
Also included are new updated pages of the 1998 TURM Manual Section 7 Automatic Transaxle-4T80-E with revised art work and text for the reverse clutch assembly. These pages are included in this bulletin as reference material for the repair of the above condition. Please also replace these pages in your 1998 TURM Manual.
1998 - revised pages are: 7-1313, 7-1314, 7-1317 and 7-1384
Parts Information
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Description Labor Time
K7000 Transaxle Use published
Assembly - labor operation
Replace time
Add For PCM 0.4 hr
Reprogramming