ABS – Another Bewildering Story
Well, I have two bewildering stories to share with you that normally would give you nightmares. However, by reading this story you will see that it really was another man’s nightmare. But for you it will be a sweet dream, since you will acquire his experience and bypass the pain he suffered.
Another Transmission Mutation – Part 1
In the never-ending variety of transmissions on the road today, there is yet another that may find its way onto your bench. A mutation from the F4A40-series transmission used in Mitsubishi and Hyundai vehicles, it’s called the A4CF2 (Figure 1). This is a four-speed transmission (Figure 2) being used in 2006 and later Kia Spectras and 2007 and later Hyundai Elantra (HD).
Which Planet Are You On?
As most rebuilders know, in 1997 the 4L80-E went to a center-gearbox lubrication system by relocating the cooler return line from the pump to the center support. As a result, many internal hard parts were redesigned to accommodate this new lubrication system, as illustrated in figures 1 through 5 taken from an ATSG bulletin.
Another Case of Mistaken Identity
When he removed the valve body and started to compare it with his original valve body, he noticed that the manual valves were different lengths. Since the valve bodies looked identical in every other way, he decided to use his original manual valve in the replacement valve body. When he installed the valve body it worked flawlessly.
Solenoid Control in the TF60-SN (09G/09K/09M)
Starting with a few four-speed automatic transmissions, increasing with the five-speeds and more so with units having six or more speeds, it is interesting to see the use of counterbalance pistons in clutch drums that drive the planetary system. Since drive-style clutches are rotational, there is a tendency for centrifugal force to creep the clutch on when it is not in use, which could cause premature damage to the frictions.
A Balancing Act
If you just read the “Technically Speaking” article in this edition of Transmission Digest you might recall that we spoke a little about how balance pistons are being used in rotational clutch drums, and their purposes. This article covers one of the problems we have seen with the C1/K1 clutch (Figure 1) as it relates to the AWF21 (Aisin TF-81SC, used in the Ford 500) and the TF60-SN (09G/K/M, used in Mini Cooper, Audi/VW) transmissions.
A Self-Inflicted Injury
There have been enough different cross-connection scenarios that ATSG could easily do a full-day seminar on the subject. The worst of all involved an R4A-EL transmission in a Mazda 929 on which the input-speed sensor was cross-connected with the heated O2 sensor. Soon after the vehicle was started, voltage from the ECM that was supposed to be going to the heated O2 sensor was being routed to the TCM because of the cross-connection error.
Oddities & Wear-Out, Part 2
Continuing this month with the information provided by Jim Dial on the U-series 140/240 transmission we cover some common wear-out areas in the valve body that can cause this unit to fail again prematurely. The best thing about this is that they are all sleeves and are easily repaired. These items were discovered as the U140/U240 Technicians Diagnostic Guide was being written.
Toyota/Lexus U140/240
In past articles and bulletins we have talked about functions of the torque-converter-clutch (TCC) solenoid on the 4L30-E family and how on BMW and 2000-up Isuzu models this solenoid is responsible for TCC application and a reverse-inhibit solenoid. The U140/240 series has “one-upped” that, as we are going to find out in the following illustrations.
AW81-40LE: The Valve Body
Picking up where we left off last month as promised, we are going to take a closer look at the valve body and the operation of the timing solenoid (see Figure 1). But before we get into it, there are a couple of things to be aware of.
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.
Another Clever Engineering Design
This month I’m revealing another very clever engineering redesign with a Ford/Mazda transmission. The Ford FNR5 is the five-speed version of the previous four-speed 4F27E. Mazda uses the 5NR5 designation for its redesigned FN4A-EL.
