Technically Speaking Archives - Page 4 of 21 - Transmission Digest
Overcharged

Wayne Colonna breaks down a 42RE with a misfire problem.

The P0776 Twist

Tom from “Transmission Shop” in Minnesota had a customer come in with a 2012 Honda Odyssey with a six-speed BYKA transmission experiencing erratic shifts. It had an intermittent and inconsistent 2-3 shift where sometimes it would have a slight flair and bump while other times it would experience a large flair and a bump. Other times it shifted into 3rd then neutral and back into 3rd.

Mercedes 7G-DCT Transmission (Part 2)

Aside from a few items such as the aux pump and the park lock solenoid, it’s a typical DCT transmission designed for performance.

Mercedes’s 7G-DCT Transmission (part 1)

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

There have been reports in the field that a garage shift from reverse to drive produces a “snapping” sound, which has been traced to a defect with the previous design output shaft assembly. Installing the “UNIGEAR” output shaft assembly seemed to have eliminated the garage shift noise.

Spring Season

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.

VLP-Line Pressure Too High

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.

CVT 7 Troubles

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

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

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. They started with what they wanted to achieve regardless of how impossible it may seem, and work their way backwards to identify what made that goal seem impossible.

When it is Broken

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.

Very Odd Issues

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