The New Jatco JF015E: When is a CVT not a CVT?
The CVT (continuously variable transmission) concept has been around forever, but CVTs have been on the road now for decades, in one form or another. Although there are several different models of CVT, they all have one thing in common: basic operation.
Over the years there have been variations in CVTs from vehicle model to model, starting with the original DAF European CVTs, up to the first Jatco CVT, Saturn VT20E, ZF VT1, Ford CFT30 and then on to later-model Jatcos. There are CVTs that use a torque converter and some that don’t. A CVT may have a push belt, while others use a drive chain. Electrical components also vary widely among models. In addition, certain models use a direct-drive pump while others use a chain-driven remote pump. The CFT30 uses a pump with oscillating pistons. A CVT will also have a planetary gear set, primarily for reverse.
JR710E RWD 7-Speed: RE5R05A plus parts/minus parts
Jatco, a Japanese transmission manufacturer, has for decades produced a variety of transmissions, and although Nissan and Subaru have been the largest consumers, several car companies use its products.
In recent years, the focus of Jatco has leaned toward CVTs (continuously variable transmissions); however, the company has always produced step-type transmissions – from simple three-speed automatics all the way up the food chain to seven-speed transmissions, like the JR710E/711E.
Jatco also launched a hybrid version of the JR710E, coded JR712E, in 2011. The JR712E concept is somewhat in line with the GM 2ML70 hybrid.
Don’t Forget to Inspect the Pins
When it comes to diagnosing vehicle issues in today’s world, so many things must be taken into consideration. You must check the integrity of all possible components that affect the subsystem you’re diagnosing. In the realm of modern automotive transmissions, those subsystems will include computer hardware, software, wiring, sometimes cabling and actuators, and the components on and in the transmission itself. I guess those old rusty bolts weren’t such a challenge after all.
Looking ‘Outside the Box’
My first encounter with a Nissan CVT was an interesting experience. Our wholesale customer had diagnosed the transmission as being bad, so the transmission was then replaced. After replacement, the vehicle owner said the car would not accelerate beyond 40 mph. Since the installed transmission was purchased from us, it then became our responsibility to find the root cause of the problem and get the transmission working properly. We verified the customer’s complaint with the initial road test and then began diagnosing the cause.
Unlocking Some 55-50 Valve-Body Mysteries
Let’s start with identifying the AW 55-50 valve body and the differences that matter when you’re choosing a replacement valve body. There are four castings, which can be identified by either a letter cast into the valve body just to the right of the S4 solenoid or a blank spot.
AW55-50SN Initial Engagements
I will try to explain one of the most-common questions being asked, concerning Drive and Reverse engagement problems. Some of this information has been covered at the ATSG seminars, so I will be using some amperage and pressure readings taken from a 2005 Nissan Altima as a visual aid so we can see how this transmission accomplishes smooth, almost-unfelt initial engagements, or garage feel as it is known to some.
Getting Up to Speed with the RE4F04B
The RE4F04B transmission is no stranger to our technical hotline, for a variety of reasons. This article is about a self-inflicted injury that occurs every so often and, when it does, makes for a very bad day.
Shining Some Light on the Problem
A 1996 Nissan 300ZX came into the shop last summer. Remember, I said it was summer, which affects this story later.
The customer said the check engine light was on and that at times the transmission would not shift into fourth gear. I scanned the computer and found a P0705 inhibitor-switch code. I cleared the code and went for a test drive with the scan tool connected. Inhibitor-switch data was correct, and the code did not reset.
RE5R05A Facts and Observations
This transmission has been on the street since 2002, when it was first used in the Infiniti Q45 with the 4.5-liter engine. Since then, Infiniti and Nissan have used this transmission in many models. There are three versions of the RE5R05A valve body…
