Mike Brown
Mike Brown
A Closer Look at GM's AF50 Transmission
In this article, we’re going to take a look at some of the basic diagnostic and repair procedures for GM’s AF50 transmission. As always, having the right information makes things easier. A clutch-and-solenoid chart is a good start (figure 1); with it, you’ll be able to see what clutch is coming on and off and what solenoid is being used to operate that clutch. That’ll help you focus on ...

GM's AF50 8-Speed vs. Toyota's U880 8-Speed: The Same But Different!
Let’s take a look at some of the changes GM made with the Aisin 8-speed FWD. One of the first things that’s different is GM integrated the park neutral switch into the TCM (figure 1). With the integrated position sensor, we now have the following advantages: Reduced number of parts Simplified wiring harness Enhanced reliability because there’s no harness circuit between the ...

GM's AF50 8-Speed Transmission Fluid Level and Condition Check
Remember the good old day’s when you just opened the hood pulled out the dipstick, wiped it off, stuck it back in, and pulled it out? Just like that, you knew if the fluid was low or not. You could look at the fluid on the stick and tell a lot by its condition. Was it burnt, varnished, or nice and red? And if you needed to add fluid, you’d just grab a quart of Type F or Dexron off the shelf...

Toyota/Lexus U880E: Beyond the Valve Body, Part 2
Welcome back for part 2 of beyond the valve body for the U880E. In the January/ February issue, we disassembled this unit down to the C-1 clutch. One piece of information that I left out was servo identification and servo travel. It’s important to be aware of what the servo travel should be (figures 1A, 1B & 1C). Using a caliper gauge, measure the Travel of the B-1 brake piston rod whil...

Toyota/Lexus U880E: Beyond the Valve Body
The Toyota/Lexus U880E was first introduced in the 2013 Lexus RX350 sport. Since then it’s become quite popular; BMW began using it in 2015 under the name GA8F22AW. GM started using in 2016 as the 8F45. And it started showing up in Volvo in 2014 as their TG-81SC. These transaxles have been on the road for about five years now and are getting a lot of miles on them. With all the different manu...

A Closer Look at the Toyota/Lexus U880 Valve Body
The Toyota/Lexus U880E was first introduced in the 2013 Lexus RX350 Sport. Since then, it’s become quite popular: It’s currently being used by BMW since 2015 under the designation GA8F22AW; GM started using it in 2016, calling it the 8F45; and Volvo began using it in 2014, renaming it the TG-81SC. These transaxles have been on the road for about five years now and they’re getting a ...

6T40/45 Diagnosis and Fixes
One of the first you need to know when diagnosing and fixing any transmission is to understand how it works. Once you understand what does what and when it’s supposed to do it, you’re more likely to know what to check first and what you don’t need to check at all. It’s never any fun to get the transmission on the bench, only to find nothing wrong internally. But if you know what the com...

Toyota/Lexus Adds Eight Speeds to the U881E
Each year we see manufacturers adding more gears to familiar transmissions, all in an effort to coax more miles out of each gallon of gas. In 2013, Toyota/Lexus created the U881E transaxle: the first front wheel drive, 8-speed, transverse-mounted transaxle, which began showing up in the Lexus RX350 vehicles. Today, you’ll find this unit in BMW, GM, and Volvo vehicles. It’s a compact transax...

Ford Torqshift/5R110: A Shot in the Dark
The Ford Torqshift came out in 2003 and over the years has exhibited its share of problems. The original solenoid body may have one or five pressure switches, depending on model year. The computer on these vehicles was never programmed to monitor the pressure switches. Ford removed them in late 2004. The later solenoid body may have one pressure switch with no wire going to it. In this appli...

A Logical Approach to Solenoid Circuit Testing
A common call to the ATRA HotLine has to do with solenoid circuit problems. Most of you have been dealing with these types of problem for years. Many of you have the answers seconds after you check for codes. If you're one of those technicians, this article may not be for you. But if you're a technician who appreciates a new look at a common problem, never dealt with solenoid codes, or are new ...

Identifying ATF Contamination
Coolant contamination has become a lot harder to identify on many of today’s transmissions. You may have to do more than just look at the fluid to find it. And that still leaves us with a new question: Is it coolant or plain water? We’ve all become accustomed to the idea that radiators can fail and allow coolant to contaminate the transmission. And there may be other signs of coolant damage...

5R55N with Wrong Gear Starts and Bindups? Look for a Faulty Servo
In 2000, Ford introduced the 5R55N. It was only used in the 2000-2002 Lincoln LS, 2002 Thunderbird, and 2000-2002 Jaguar S-type. It’s a lot like the 5R55W/S, but the N model has an intermediate clutch; the W/S models don’t. Ford introduced the 5R55W/S in 2002 and, by now, you’ve probably become pretty familiar with the ins and outs of this unit. Some common problems include slipping in 2n...

Circuit Diagnosis Made Easier by Looking at the Big Picture
Cadillacs have always given diagnosticians headaches when it comes to diagnostics. Let’s not kid anyone here: the Cadillac has twenty plus modules, miles of wiring, and controls for just about everything including the kitchen sink. So when it comes to diagnostics, the trick is to keep it simple. Here we’re going to talk about a 2005 Cadillac STS with the MIL lit; the only complaint was that...

Blown Away by High Pressure
Remember the Dodge truck we talked about in the January 2015 issue? The 2003 Dodge Ram 3500 5.9 diesel? This is what happened to the front clutch (figure 1).  The truck came in with the front clutch blown apart; the shop replaced the drum, only to blow the new drum apart while it was still on the lift.  After replacing the valve body with a new, stock valve body, the pressure dropped do...

Toyota/Lexus 8-Speed Transmission Is Here!
Toyota and Lexus 8-speed transmissions are on the road and are already showing up in shops. The first to be introduced was the AA80E, which appeared in the Lexus GS 460 2008-11, Lexus IS F 2008-14, and Lexus LS 460 2007-14. That was followed by the AA81E, which showed up in the Lexus GS 350 2011-14, Lexus IS350/350C, and Lexus IS250/250C 2014-up. Use the chart to identify the difference b...