K 3500 Truck 4WD V8-6.6L DSL Turbo VIN 1 (2001)
Fluid Pressure Sensor/Switch: Customer Interest
A/T - 4L60-E 1-2 Shift Shudder/Slipping/Vibration
Bulletin No.: 02-07-30-030A
Date: November 18, 2003
TECHNICAL
Subject:
Transmission 1-2 Shift Shudder, Vibration, Slips, Chuggle (Install Generator Voltage Sense Circuit)
Models:
2001-2003 Chevrolet Silverado
2001-2003 GMC Sierra
with 4L60-E Automatic Transmission (RPO M30)
Built Prior to August 5, 2003 at Oshawa (Plant Code 1) and Pontiac (Plant Code E) or Prior to August 12, 2003 at Fort Wayne (Plant Code Z)
Vehicles built AFTER the dates listed above will have a Voltage Sense Circuit internal to the generator. These vehicles will NOT have a wire in terminal
D of the generator connector.
Supercede:
This bulletin is being revised to accommodate for a 2003 model year mid-cycle enhancement. Please discard Corporate Bulletin Number 02-07-30-030
(Section 07 - Transmission/Transaxle).
Condition
Some customers may comment that the transmission slips, a shudder, chuggle, or vibration is felt when the transmission shifts from first to second gear.
Cause
A 12 Hz electrical feedback from the charging circuit may be affecting the transmission pressure control solenoid, causing a fluctuation of the line
pressure within the transmission.
Diagnostic Tip
Road test the vehicle under the following conditions:
^
Throttle position is less than 15 percent.
^
Engine coolant and transmission fluid are at full operating temperature.
^
The outside ambient temperature is warmer than 24°C (75°F).
If the condition is present, disconnect the generator 4 cavity connector (2 wires in the connector) and retest.
If the condition is no longer present, perform the correction listed below.
If the condition remains unchanged, the condition will not be corrected with this procedure. Look for other causes of the condition.
Correction
Install an external sense lead to the generator assembly. This is accomplished by adding a wire from the generator four wire connector to the generator
output BAT terminal.
1.
Disconnect the negative battery cable from the battery/batteries.
2.
Slide the protective boot on the generator BAT terminal aside and remove the retainer and wire cable from the BAT terminal.
3.
Unplug the generator 4-cavity terminal from the top of the generator.
4.
Inspect cavity D on the generator connector for a red cavity plug.
^
If a red cavity plug is present, it is not necessary to replace the generator connector. Remove the CPA and save. Remove the red cavity plug
and continue with step 9.
