In this continuation from Part One, we’ll be discussing the rotating clutches, planetary gear sets and more on the 9T50.
The 6T70 / 6F50 and 6T40 / 6F35 transmission families have undergone countless changes since 2007 and are used in a variety of different models of vehicles currently.
Certain aftermarket serpentine belts can create an electrostatic discharge that can impact electrical components that happen to be too close, such as the TCM. In this particular model truck, the TCM is not too far away from the belt, and that was causing the erratic transmission operation and trouble code.
The frustrated owner of a 1996 Mercedes S500 called to complain that his vehicle had been acting up for some time and he was at his wits end. Apparently, he and others had taken a swipe at repairing the problem with little success so the vehicle was towed into the shop to get a look with a fresh pair of eyes, so to speak.
Toyota has been producing automatic transmissions almost from the beginning of time achieving various levels of success in durability within their fleet. Over the years there have been incidents of Toyota developing transmissions for other car companies, domestic and overseas.
Unlike the 6R60 / 6R80 models that were a carryover from the ZF6HP26, Ford started with a clean sheet of paper in the development of the 6R140. To say that this unit is a beast would be an understatement due to the fact that it weighs more than 300 pounds.
After General Motors and Ford collaborated on the GM 6T70 and Ford 6F50 transmissions, they recognized the need for another transmission to accommodate lighter-duty vehicles.
During development, the GM 6T70 and Ford 6F50 basically fell off the same sheet of paper resulting in a noticeable amount of interchangeability of various components. One key difference between the two models is that GM chose to go with a mechatronic (TEHCM) valve body design, whereas Ford stuck with the traditional external TCM (PCM). Another variable between the GM and Ford transmissions were the dreaded cushion springs that have been tweaked over the years. Both designs accommodate the larger vehicles equipped with higher output engines and both have received continuous changes and upgrades.
There was a time, long ago, when the owner of a vehicle would experience a transmission problem and roll into a repair facility to have it addressed. The issue would be diagnosed, the offending components would be repaired or replaced, and once done final adjustments would be made either before or after a thorough road test. Fine tuning was limited to the adjustment of a throttle rod or cable, turning a screw a couple of times on a modulator, or changing a spring on a governor. So much for the good old days!
Little did the owner of a 2005 Acura MDX know that at the time the transmission in his vehicle was being repaired that it was the start of a long uphill battle. The vehicle initially was towed into a shop for inspection due to a no-movement condition. In addition, the check-engine light was on indicating the presence of trouble codes, several of which were verified on a scanner.
By the time that the owner brought the vehicle to the shop, the chatter while on a turn was pretty consistent, especially when hot. The Subaru was a 2004 Forester AWD equipped with a 2.5L non-turbo engine and four-speed automatic transmission. The vehicle had 97,000 miles on it and was in great condition. The engine ran well and the transmission functioned fairly well considering the mileage, except of course for the chatter. It didn’t appear that anything was ever done to the transmission.
The second part of this two-part presentation involves planetaries, filter and valve body.