A/T - Allison 1000 Series Shift Busyness

File In Section: 07 - Transmission/Transaxle

Bulletin No.: 01-07-30-034

Date: November, 2001

TECHNICAL

Subject:
5-4 Shift Busyness (Excessive Shifting) While Using
Cruise Control and Towing (Reprogram PCM)

Models:
2001 Chevrolet and GMC C/K 2500/3500 (3/4 and 1 Ton)
Series Pickup Models (Silverado and Sierra)
with 6.6L Diesel Engine (VIN 1 - RPO LB7)
and Allison(R) Series 1000 Automatic Transmission (RPO M74)

Condition

Some customers may comment on 5-4 shift busyness (excessive shifting) when towing a trailer and using cruise control. This condition usually occurs on roadways with an up and down (hilly) surface grade.

Correction

To improve excessive shifting, reprogram the Powertrain Control Module (PCM) using the new calibration listed below.

Calibration Information





This calibration is an electronic calibration and is NOT available from GMSPO. It will be available from Techline starting October 2001, on the TIS2000 version 10.0.

Warranty Information





For vehicles repaired under warranty, use the table.





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