C 3500 Truck 2WD V8-6.6L DSL Turbo VIN 1 (2002)
Control Module: Technical Service Bulletins
A/T - TCM Fast Learn Procedure Requirement
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 02-07-30-032A
Date: November, 2002
Subject:
Allison(R) Transmission Control Module FastLearn Procedure Update Required After Transmission Repairs
2002-2003 Chevrolet Silverado
2002-2003 GMC Sierra
with Allison(R) 1000 Series(TM) Automatic Transmission
This bulletin is being revised to change a labor operation number. Please discard Corporate Bulletin Number 02-07-30-032 (Section 07 -
Transmission/Transaxle).
A new "FastLearn" procedure has been released for the Allison 1000 Series(TM) Transmission. The "FastLearn" procedure must be completed any time
the following vehicle repairs are performed as shown.
The "FastLearn" procedure is a series of tests that are run to allow the Transmission Control Module (TCM) to "Learn" (Adapt) to the characteristics of
the clutch packs within the transmission. As each clutch packs data is learned, "FastLearn" stores the information in the adaptive cells for each clutch
within the TCM. "FastLearn" will allow a repaired Allison 1000 Series(TM) transmission to be road tested after completion of the repair in as
near-fully-adapted state as possible. This will allow the technician and customer to drive the vehicle in the adapted mode and reduce the number of
technician and customer concerns after a transmission repair. The "FastLearn" procedure consists of four (4) steps (modes).
Park Mode
While the transmission is in Park with the engine idling, FastLearn will cycle through a series of tests where the C3 and C4 clutches are repeatedly
applied to learn their clutch characteristics. During the C3 and C4 clutch apply/release procedure, FastLearn is able to characterize the A and B solenoid
pressures corresponding to clutch return springs, and is also able to learn the volumes for C3 and C4 clutch packs. In addition, C5 clutch is repeatedly
applied and released in Park to purge out air for later learning of its clutch volume.
Drive Mode
Caution:
While in Drive, if the Tech 2 loses communication, or becomes disconnected, the vehicle may remain in Drive and could move forward if the wheels
have not been securely blocked.
Once all of the Park test data have converged, the Tech 2(R) instructs the driver to select Drive. Once Drive is selected, the TCM engages C1 clutch to
obtain Drive and C1 clutch volume. The TCM repeats this test until the volume learned for C1 clutch has converged.
Reverse Mode
Caution:
While in Reverse, if the Tech 2 loses communication, or becomes disconnected, the vehicle may remain in Reverse and could move backward if the
wheels have not been securely blocked.
The Tech 2(R) will instruct the technician to select Reverse. When Reverse is selected, the TCM engages C5 clutch to obtain reverse and learn the C5
clutch volume. The TCM repeats this test until the C5 clutch volume has converged.
After learning C1 and C5 clutch volume, FastLearn updates the adaptive volume data for all shifts with either C1 or C5 on-coming clutch.
