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.
Friendly Rivalry Builds Success
Four years later, the results of the collaboration were two very similar (though slightly different), highly efficient, 6-speed transmissions. They boasted a 4% increase in efficiency over similar vehicles with automatic 4-speeds. Ford decided to name their models 6F50 and 6F55, while GM decided on 6T70/6T75/6T80. Ford has used their transmissions in the Edge, Taurus and Escape, to name a few; while GM has used them in the GMC Acadia and Terrain, and Chevy Impala and Traverse.
ZF8HP55 transmission
Sonnax has a set of vacuum diagrams for the ZF8HP55 transmission.
Ins and Outs of Torque Converters
Ed Lee presents a two-part project about the ins and outs of torque converters, starting with the outs.
Adjusting Infamous THM700-R4 Throttle Valve Cable
If the transmission happens to shift early after the coarse adjustment, grab the cable adjuster so it doesn’t move, and push the release button, and then move the cable back toward the bracket a few clicks. After you get the transmission to shift at the right speed for the 1-2 and 2-3 shifts, you are ready to verify the transmission has a full throttle 2-1 down shift.
Very Odd Issues
Wayne Colonna illustrates the odd issues that pop up with valve body bolt lengths with an example of Toyota’s U660.
10R80/10L90 10-Speed Solenoid Function
The first thing to remember when replacing the valve body and/or just the solenoids is the TCM will have to be updated. This is very similar to what has been covered in the past with the 8L90 found in GM vehicles referred to as solenoid characterization. The 10R80 solenoids are similar to the 6R140W solenoids referred to as solenoid body/strategy identification.
An Inflated Story about Erratic Shifting
After a wide-open throttle forced downshift and then coming to a stop, the vehicle would take off in third or fourth gear. A scan tool confirmed that the wrong gear starts were commanded by the TCM. The transmission would upshift from third or fourth gear to fifth and sixth gears.
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.
Another Day at the Orifice
Modifying orifice size in valve body separator plates has been practiced as long as automatic transmissions have been in existence. From performance upgrades to attempting to fix problems caused by valve-body wear, opening up orifices can provide positive effects – but can just as easily cause unforeseen problems. To avoid unwanted results, it is necessary to know when to drill, what size to drill to and when not to drill.
Extreme Stator Repair
When you are rebuilding a late model converter it is very important to have the correct stator, impeller and turbine. The computers in today’s vehicles are sophisticated enough to pick up small changes in the stall or stall torque ratio in a converter. If a change is detected by the computer it will set a code.
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.
