Technically Speaking Archives - Page 5 of 21 - Transmission Digest
The P0763 Headache

A call came in to ATSG’s technical help line concerning a 2009 Kia Borrego with a 3.8L engine using a 5-speed RWD transmission called the A5SR2. This transmission is very similar to the Subaru 5AT transmission, a derivative of Nissan’s RE5R05A transmission. Mounted on top of the valve body are the solenoids, a sub-ROM and pressure switch frame assembly.

An ECU Dilemma

A 2009 Toyota Corolla LE with a 1.8L engine and a U341E transmission arrives to a shop with code P2757 Torque Converter Clutch Pressure Control Solenoid Performance (SLU Solenoid) Malfunction stored. The unit was removed and overhauled with a new SLU solenoid and a replacement torque converter. When it was tested, the car seemed to be working well but the Malfunction Indicator Lamp came on after reaching highway speed.

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.

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.

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.

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.

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.

A ‘Guess Why’ Tech Article

A 2006 Ford Focus 2.3L with a 4F27E transmission comes into a shop with a complaint of a harsh garage shift into gear (drive and reverse), as well as harsh lift throttle coast downshifts. All forward upshifts are perfect. There are no codes stored in the system. In some cases, the transmission had been rebuilt, which included a different valve body and solenoids in an attempt to resolve the problem.

It Doesn’t Move and I Cannot See Why

A Nissan or Infiniti vehicle using the RE5R05A transmission may come into the shop with a no-move complaint. Or, a unit still under your warranty comes back with a no-move condition. And worse yet, you take it apart and see nothing wrong. The transmission is rebuilt that includes changing the torque converter and valve body as an attempt to fix the no-move problem. The unit goes back into the vehicle and still no movement. Could it be a bad TCM?

Connector Blues

Wayne Colonna focuses on water contamination of the C134 connector in an FNR5.

A 2009 Ford Fusion 2.3L coupled to an FNR5 transmission comes in to a shop with a host of solenoid codes, gear ratio codes and speed-sensor codes…