First thing Monday morning the call comes in on a Ford F350 Lariat, 6.7 liter dually with all the bells and whistles. It blew the converter while plowing snow; not so surprising when you consider how much abuse these trucks take in the winter, especially when there’s a heavy blanket of the white, fluffy stuff.
The torque converter was blown: There were converter clutch pieces all over the bottom of the pan. A complete inspection confirmed that the torque converter came apart.
The owner of the vehicle wanted a factory torque converter, so they ordered one from the dealership nearby. But the torque converter from the dealer had only six studs instead of the original eight (figure 1), so they sent it back to the dealer thinking they got the wrong part delivered.
When the dealer received the torque converter, the parts guy called the shop and asked why. The tech explained that the converter in the vehicle had eight studs, not six like the one they sent.
The parts guy went on to explain that, beginning production of the 6R140 transmission in 2011, the torque converter and flywheel were changed for diesels. The old torque converter and flywheel with the 8-stud pattern are no longer available from Ford. The converter has been updated to a 6-stud pattern for diesel applications.
Remember this is only for diesel engines; the torque converter for gas engines is still the same 4-stud pattern, Ford P/N CC3Z-7902-C.
The old, 8-stud torque converters are scarce but are sometimes available through the aftermarket. The reason for the update is cost of manufacturing.
So, when you’re working on a 6R140 behind a diesel, if you want to use a factory converter, you’ll need to replace the flywheel and torque converter as a set, using the updated, 6-stud design. Presently they’re only available from Ford, so they’re a bit pricy — about $900 for the set! — but well worth the investment:
Torque Converter CC3Z-7902-D
Flywheel CC3Z-6375-A
You’ll also need a couple special tools to install the torque converter without damaging the front seal: part numbers 307-651/1 and 307651/3 (figure 2). You can find these tools on line at www.oepartsstore.com. They also offer the new converter, flywheel, and nuts at a discounted price.
