Thank you Cody.

So, must a certain gear be engaged before the TC locks? Meaning, is it possible the PCM will lock the TC in any gear (1 thru 4)?

 

Depends on the PCM strategy.

1st and 2nd gear TCC apply CAN be done for most computers out there though....just depends on who's tuning it.

 

Greg,

Thanks for the feedback on the updates. I know I'm back a few versions, I had kept it up to date but lost my hard drive. I assumed that I couldn't get updates after 12 months. I'm not sure if I have the proline connector. I have the PC based Ford bundle with a usb connector.

Curtis,

The truck does not have a programmer. I know that it did at one point (the pcm cover is cut). I suspected that it had a screwed up load and had the dealer reflash it last summer. Didn't make a difference. The PCM is a NVK4 if that helps.

Cody,

Thanks for all the invaluable information. It's really starting to make sense.

Does anyone know how the transmission controls the TC lock-up once the pcm tells it to lock?

Thanks
Dave

 

When the PCM commands lock the Torque Converter Clutch (TCC) solenoid is energized. That vents pressure on one side of the torque converter clutch. The pressure on the other side of the clutch presses the clutch plate against the torque converter cover.

 

What? Converting your lights over to LEDs has some other effects? I was just looking to do just that here real quick. I had no idea there were downstream issues with it.

Sorry to derail OP if this does...

 

Thanks Mark!

So where does the TCC live in the transmission? Is it part of the valve body? Can there be failures with the solenoid or valve that can cause erratic engagement? Is it a progressive solenoid or just an off on switch?

I know, a lot of questions but I'm just trying to get my head around this part of the system.


For the LED lights, my understanding is that they can effect the sensing side of the circuit due to their low current draw and lower resistance. Basically the system has a hard time seeing that the brakes have been activated. Last year I saw a tsb about the IDM I think that refers to a blown tail light as causing issues. LEDs can do the same thing. The cheap ones can also emit a lot of EMF too that can effect things.


Thanks
Dave

 

One more thing I should add to this that may explain my line of questioning is that before I purchased this truck, it had a major transmission failure. The DPO (dumb previous owner) had it rebuilt at a local AAMCO..... The receipt lists an overhaul kit and rebuilt TC only. No mention of a cooler, or shift kit. It also goes on to say in hand writing that the warranty would only cover the parts that they installed makes me think the PO refused to replace some stuff that was recommended When I test drove the truck and noted that it had really firm shifts, the PO told me it had a shift kit installed. I got the truck cheap enough that I was prepared for a rebuild if necessary.

This is part of the reasoning that makes me wonder if this could be caused by a blocked cooler, bad valve body, poorly installed shift kit, or a bad TC. I do plan to install a 6.0 cooler but am trying to figure out if I have a bigger issue that should be addressed while the pan is off or before I install a high dollar cooler.

Thanks
Dave

 

It's on the solenoid body inside the pan. The solenoid and/or the torque converter valve can be intermittent. The solenoid is progressive.

Yep.

I doubt that a cooler or a torque converter could cause this. The shift kit or valve body could do it.