Technically Speaking

Mercedes 7G-DCT Transmission (Part 2)

Thursday, August 1, 2019 12:00 AM

Last month’s article spoke about the susceptibility vehicles have with this transmission to bottom out and break the case. Having one of these on our bench here at ATSG (Figure 1), we will take advantage to look inside this transmission to see what it looks like.
Mercedes’s 7G-DCT Transmission (part 1)

Monday, July 1, 2019 12:00 AM

Several years ago, Jan ten Klooster, an excellent tech in Amsterdam sent me pictures of the 7G-DCT transmission that came out of a 2013 Mercedes CL A 200 1.6L vehicle (Figure 1). This dual clutch transmission came out in 2011 in both the A and B class vehicles. The reason such a new vehicle came in to Jan’s shop for repairs is the owner had inadvertently bottomed out the car breaking the transmission’s case.
No Forward Good Reverse - A Leave Out or a Blow Out

Friday, May 31, 2019 12:00 AM

Wayne Colonna discusses the UNIGEAR output shaft assembly.
Technically Speaking: Spring Season

Wednesday, May 1, 2019 12:00 AM

A 2006 FORD Explorer with a 4.0 engine using the 5R55W/S type transmission came back to Jeremy at Warren Transmissions 8 months after the original rebuild. The customer stated that all was good prior to climbing a hill when it felt like he was losing power and the engine began to rev quite high like the trans was slipping. Customer said he managed to nurse it home.
Technically Speaking: VLP-Line Pressure Too High

Monday, April 1, 2019 12:00 AM

A 2014 Dodge Journey 2.4L with a 41TES transmission came in to Electronica & Transmisiones in Buenos Aires Argentina. It had code P0869 set for Line Pressure High. Leonardo Luercho went out with the vehicle using his scan tool to begin his diagnostic approach. While observing the data parameter IDs in his scan tool, he noticed that there was a difference between desired and actual line pressure. Figure 1 is a photo of the graph displayed in his scan tool. The blue, more-active line is actual line pressure provided by the VLP sensor. The black, less-active line is the desired command given to the VLP solenoid by the computer.
Technically Speaking: CVT 7 Troubles

Friday, March 1, 2019 12:00 AM

Wayne Colonna discusses the issues with the CVT7 transmission.

The CVT 7 used in Mitsubishi and Nissan vehicles (Figure 1) is unique in that between the pulley assembly and the differential is a planetary gear set controlled by a reverse brake, a low brake and a high clutch.
Suburu 4AT Phase ll Version ll Control and Valve Body Changes

Friday, February 1, 2019 12:00 AM

Sometime at the beginning of the 2004 model year, Subaru redesigned the 4AT Phase ll Control system that placed the transfer clutch control solenoid into the valve body. The new design valve body (referred to as Version II) contained 3 clutch control solenoids, 2 brake control solenoids, a TCC and pressure control solenoid (Figure 1).
Mazda’s SkyActiv-Drive 6-speed automatic unit: Magnet is Loaded with Metal

Wednesday, January 2, 2019 3:54 PM

The progressive development of Mazda’s “SkyActiv®” engine and transmission has resulted in an engine that should be available in 2019 called the “SkyActiv-X.” The name SkyActiv given to this drivetrain reflects their back-casting developing method.
Technically Speaking: When it is Broken

Saturday, December 1, 2018 12:00 AM

Planetary gear sets and their operation are unappealing for many. Know what is turning and what is holding for each gear can challenge one’s thinking. Particularly so when there are 10 speeds and 3 planetary gear sets involved. I actually enjoy pushing my mind to visualize powerflow and indeed, it can be challenging at times. But it sure does go a long way when trying to isolate a noise problem. It also helps when you have missing gears or no movement. This too helps to know where to look. A perfect example of this is in the Technically Speaking column back in December 2017.
Technically Speaking: Very Odd Issues

Thursday, November 1, 2018 12:00 AM

Wayne Colonna illustrates the odd issues that pop up with valve body bolt lengths with an example of Toyota’s U660.

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