A/T - 1st to 2nd gear Shift Shudder

[permx11]

Take a look at this TSB.

A/T - 1st to 2nd gear Shift Shudder

File In Section: 07 - Transmission/Transaxle

Bulletin No.: 02-07-30-030

Date: August, 2002

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)

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

[mackin]

Doesen't appear to be Allison related ..... That's a good thing ....

MAC :D :D :D

[dmaxalliTech]

That tsb pertains only to the 4L60E found in the 1500 trucks. Condition is usually only noticed when ambient temps are high, above 70 degrees and vehicle is at operating temp. You need to replace the connector at the alt, add a sense wire to it and hook it to the battery wire on the alt. We performed so many of these re-wires that I prepared up about 10 of these connectors so repair only took about 5 minutes. Warmer weather is coming, better make up some more! Alli guys dont have to worry about this.