2001 silverado tranny shifting

Yer probably going to have to get the codes scanned. As to why it's doing it-good likelihood yer losing line pressure to the clutches. Has this trans been serviced (pan drop and filter change) in the 35,000 miles? Hang in there.

Respectfully submitted,

Loren Knighton Woodland, CA.

Under the hood since 1964 Member TRNI IATN

I think this is what your after...

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Transmission 1-2 Shift Shudder, Vibration, Slips, Chuggle (Install Generator Voltage Sense Circuit) #02-07-30-030

Transmission 1-2 Shift Shudder, Vibration, Slips, Chuggle (Install Generator Voltage Sense Circuit)

2001-2003 Chevrolet Silverado

2001-2003 GMC Sierra

with 4L60-E Automatic Transmission (RPO M30)

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.

Document ID # 906809

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4L60E Shift Shudder 1-2 Shift Light Throttle Hot #PI00120A 4L60E Shift Shudder 1 - 2 Shift Light Throttle Hot . When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms. Condition/Concern: The 4L60E automatic transmission may experience a shudder on the 1 - 2 shift. The concern is duplicable under light throttle conditions with the transmission and engine at full operating temperatures and ambient temperatures 70 - 100°F. Recommendation/Instructions: The following components will be required to complete the repair. 1 Connector Replacement Pack Part Number 15306009 1 Ring Connector Part Number 02984172 (sold in packages of 10) Bulk RTV sealer. Note: Use approved methods outlined in SI to remove and install wires into the connector. Disconnect the negative battery cable. Remove the 2 wire 4 cavity connector from the generator. Remove the brown wire from cavity "B" and the gray wire from cavity "C". Remove the wires "B" and "C" from the service connector part number 15306009 and discard. Install the brown wire from the vehicle harness into cavity "B" of the service connector. Install the gray wire from the vehicle harness into cavity "C" of the service connector. Install the TPA retainer on to the service connector and install the connector onto the generator. The existing wire in cavity "D" of the service connector must be connected to the battery terminal on the back of the generator using ring terminal 02984172. NOTE: The serrated teeth of the ring terminal must be flattened before installation. The existing wire in cavity "A" of the service connector should be trimmed flush with the TPA and sealed with RTV to prevent corrosion. Connect the negative battery cable. Important: DO NOT use the butt connectors supplied in the service package as corrosion may occur at a future date. Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms. GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information. WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION © Copyright General Motors Corporation. All Rights Reserved.

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