B3000 4WD V6-3.0L OHV (1995)
Engine Control Module: Customer Interest
A/T - Shift Shock/Bump on 2nd to 1st gear Downshift
Bulletin No. 003/98
Issued 04/08/98
Revise
Category
K (05)
Applicable Model/s
1995 B-Series with A/T
Subject
SHIFT SHOCK OR BUMP ON 2-1 DOWNSHIFT
BULLETIN REVISION NOTE
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The WARRANTY INFORMATION section of this bulletin has been revised.
APPLICABLE MODELS
1995 B-4000 Series with automatic transmissions.
DESCRIPTION
A slight shift shock or 2 - 1 coastdown bump may be felt during deceleration with no MIL light illumination. This condition may be caused by the
calibration of the PCM (Powertrain Control Module). A revised PCM is available to reduce this condition. Customers complaining of this concern
should have the vehicle inspected and if necessary, repaired according to this bulletin.
IMPORTANT
This modification is authorized only for the listed engines and calibrations. Performing this modification on other engines and calibrations could
create liability under federal and local laws.
INSPECTION AND REPAIR PROCEDURE
1.
Verify the concern.
2.
Perform normal Workshop Manual diagnostics, including line pressure test and checking the ATF level and condition. Repair as necessary.
3.
Confirm that the vehicle has one of the old calibration numbers listed in the Parts Information and does not already have a modified PCM.
^
If the vehicle has one of the old calibration numbers and does not have an Authorized Modification Label which refers to this bulletin, install
the applicable modified PCM as listed in Parts Information.
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If the vehicle does not have one of the old calibration numbers or has a revised PCM or "Authorized Modification" label, refer to the
Workshop Manual troubleshooting and repair information.
NOTE:
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The calibration number listed on the driver's side B-pillar will remain the same even after the PCM is replaced. For this reason, it is
important that technicians inspect the radiator support for the "Authorized Modification" label to prevent unnecessary pan replacement.
4.
List the date, dealer number and this Service Bulletin number on the "Authorized Modification" label and attach the label to the radiator support.
NOTE:
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The "Authorized Modification" label will inform technicians of the PCM change if future repairs are necessary.
5.
Verify the repair.
