AW81-40LE: A Brief Introduction - Transmission Digest

AW81-40LE: 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.

AW81-40LE

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

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.

You May Also Like

GM 6T40 Pump Identification Guide

The 6T40 was introduced in 2008 for General Motors front-wheel-drive cars in the Chevrolet Malibu and has gone through several changes throughout its three generations, specifically in the pump area. The 6T40 is closely related to the more lightweight 6T30 and the heavier duty 6T45 and 6T50. Generation one started phasing out during the 2012

The 6T40 was introduced in 2008 for General Motors front-wheel-drive cars in the Chevrolet Malibu and has gone through several changes throughout its three generations, specifically in the pump area. The 6T40 is closely related to the more lightweight 6T30 and the heavier duty 6T45 and 6T50. Generation one started phasing out during the 2012 model year. The generation two pump had a slightly different pressure regulator valve, but overall the first two 6T40 generations had the same pump layout.

Seeing the Forest AND the Trees

They say that the proverbial phrase “I couldn’t see the forest for the trees” means that a person or organization cannot see the big picture because it focuses too much on the details. Related Articles – The Manifold Pipeway – 8L90 Vacuum Testing – 4L60E Harsh 1-2 Shift I have seen this phrase used after

The Manifold Pipeway

The Honda six-speed transmission has been on the bench of many specialty shops for one reason or another (figure 1). But, for those of you who have yet to lay your hands on one, mounted on the upper side of the unit is one of the largest, if not the largest solenoid and pressure switch

8L90 Vacuum Testing

Below are the diagrams for vacuum testing GM 8L90 transmissions. Note: OE valves are shown in rest position and should be tested in rest position unless otherwise indicated. Test locations are pointed to with an arrow. Springs are not shown for visual clarity. A low vacuum reading indicates wear. For specific vacuum test information, refer

4L60E Harsh 1-2 Shift

The 4L60E transmission platform has been in service from 1993-2015; that’s 22 years. It amazes me when a transmission that has been around for this long can throw a new twist on a common problem and blindside you. Let us have a look at the systems and potential problems in a 4L60E that can cause

Other Posts

Shift Pointers: No ball, no reverse

Yoram Levy from Israel gave us a call with a 2022 Chevrolet Traverse using a 9T65 that suddenly lost reverse. He had found a check ball missing in his valve body which he points out in figure 1 (above). Related Articles – Powertrain industry directory and buyer’s guide 2023 – The multi-functional Clutch 1 in

Shift-Pointers-March-Figure-1-1400
Shift pointers: A 4T65-E that wants to move in Park and Neutral

When conducting ATSG seminars, as we are usually covering a specific piece of tech, we’ll often tell attendees that if they put this together wrong, they should let us know what happens. Just recently, Ricky Hodgkinson from AACTION Transmission did just that. He was kind enough to share an incident he recently had with a

ebulletin-feb-feature-1400
Shift Pointers: Reassembling GM pumps with cam failure

For the past several years, GM has used a binary positive displacement vane type pump. The compact design allows for it to be utilized in off-axis applications such as the 8L90 transmission and the third generation 6T40 transmission. Figures 1 (above) through 4 display a view of this style pump in the 6T40 applications. Related

Transmission slipping in fifth gear: An elusive cause of a common problem

Sometimes, finding the cause of a complaint isn’t as straightforward as one would expect; sometimes, these causes can be very elusive.

December-Shift-Pointers-Figure-1-1400