A Clever Variable Cylinder Management Fix
As quiet as the drive may be, this technology has turned into big headache for both the manufacturer and the vehicle owner. This system is known to have the potential for misfires, high oil consumption fouling the plugs, repeated failure of the motor mounts and damage to the torque converter. In fact, the 2015 ATSG seminar covered a scenario where VCM activation can be misinterpreted as a torque converter shutter.
A Sudden No Move
It’s always unsettling when a transmission comes back after the customer has had it for only an hour; especially when it came back on a hook. Such was the case at a local transmission shop with a 42RE transmission.
7 G-Tronic Plus Generation Six – Part 1
Mercedes’ 7-speed transmission known as the 7 G-Tronic is commonly referred to as the 722.9 transmission. This 5th generation of Mercedes’ transmission lineup made its first appearance in 2003. By 2010 a revised version of this transmission was developed making it the 6th generation of transmissions calling it the 7 G-Tronic Plus.
The Variable Line Pressure Solenoid
The 41TES and the 42RLE-VLPS are known to produce a “Line Pressure to High” code P0869 due to defective TCM/PCM’s immediately after a 2-3 shift. When this call comes in on our help line, we ask the tech involved to run some tests so we can be certain that a defective computer is the cause. Being a pattern failure, a repair tech can be as costly as buying a computer that doesn’t fix the problem and makes for a bad day.
TCC Engine Surge
A 2008 Honda Accord using the B97A transmission behind a 3.5L engine was brought to Newmarket Transmissions from a general repair shop to be rebuilt. They had changed the radiator and when topping off fluids, they noticed the “strawberry milkshake” condition of the transmission fluid. The radiator was also contaminated with the milkshake condition as seen with the deteriorated cap in Figure 1.
Something Amiss with Planetary System
You may remember back in the early days of the 41TE transmission (A604), the sun gear was known to shear off the shell. The result would be no reverse; it would take off in 1st gear but when it shifted into 2nd it would neutralize. With 2nd gear being failsafe, it would default to a neutral gear. The vehicle would then have no movement both forward and reverse. Once the ignition was cycled off to on, you could once again take off in 1st and shift into a no-move condition.
6L80 Filter Crush
The transmission we are talking about is the 6L80 family of transmissions. It’s quite surprising to know the many times we have encountered this installation error. It is essential that the entire pan be fully supported by a saddle to distribute the pressure evenly across the bottom of the transmission. This will prevent damage to both the pan and filter resulting in immediate failure of your rebuilt transmission.
K313: A Very Simple Little CVT
Last month we removed the pump from the main case and looked at its unique design. Looking back at the transmission with the pump removed, the forward clutch drum assembly comes into view. The outer lugs on the drum are used to excite the turbine shaft speed sensor. The rpm signal from this sensor can be compared to the engine rpm signal to monitor converter clutch apply. Like a conventional transmission, when the clutch is fully applied, both values should be identical.
Beware of Code P0720: Part 2
When the computer observed an increase in rear prop speed as a result of the axle popping out, it determined the front vehicle speed sensor as being faulty due to it decreasing in rpm. Of course the loss of rpm was due to the loss of power. The computer either didn’t or couldn’t distinguish the difference. Nonetheless, the front vehicle speed sensor was being blamed when nothing was wrong with it or the transmission. Considering the strain this had on the transfer clutch with the axle popping in and out, it explains why they were burnt originally.
Toyota’s K313: Examining hydraulic system
We left off last month having already pulled the valve body from this little Toyota CVT unit. Once the valve body is removed, the 2-wire Hall-Effect turbine-shaft speed sensor (NT) can be seen bolted to the case where it reads the rotation of the forward clutch drum assembly.
Toyota’s K313 Continuously Variable Transmission
In 2014, Toyota introduced the K313 Continuously Variable Transmission in their 1.8L Corollas vehicles. It utilizes a torque converter eliminating a forward or reverse clutch-release strategy when in gear at a complete stop. The torque converter neck is a double-ear drive design that indexes into the inner pump gear.
Get the Clip Instead of Getting Clipped
The pump shaft on a Subaru transmission is keyed to the converter and held into place with an inner circlip. Those who are familiar with this know to carefully pull the converter far enough out to clear the shaft from the transmission.
