Shift Pointers
- Subject: Design and operation
- Unit: AW81-40LE
- Vehicle Application: 2004-up Chevy Aveo
- Essential Reading: Rebuilder, Diagnostician
- Author: Wayne Colonna, ATSG, Transmission Digest Technical Editor
Part 1 – a Brief Introduction
The 4 speed electronically shifted FWD AW81-40LE transmission (see Figure 1) used in Chevy Aveo vehicles since 2004 looks as if it had been constructed using parts that were left over from Toyota and Volvo transmissions. All kidding aside, it is a very straightforward transmission, making it easy to become familiar with it, as you can see by reviewing figures 2 through 4. Figure 2 is the shift application chart, Figure 3 shows clutch locations and Figure 4 shows solenoid locations.
As you look at these illustrations, you will notice the use of a timing solenoid. This is a normally closed solenoid and is used to time the 3-4 and 4-3 shifts by controlling the application and release of the forward (C1) clutch. It also prevents a reverse engagement should reverse be selected at 5 mph or greater.
Part 2 of this article will take a closer look at the timing solenoid and related valves, as they can cause a variety of issues when they fail. Until then, figures 5 and 6 provide case-passage identification for helpful rebuild information should one of these units roll into your shop for repairs.
Thanks to Alto Products for the use of this transmission.
