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TQC Fails To Lock Up


So, the new TQC is in.

And it's not doing anything differently than it did before.

As long as the car is cool, and just got to operating temp, the TQC will lock up. Let it go about 10 more minutes, and it won't lock up any more.

The shop, of course, will need another 2 weeks to fix it, since they didn't troubleshoot anything in the first place, so before I take it back to them, I'd like to give them a little guidance in the right direction.

Are there any wiring issues that I would need to consider that might be affected by the temp of the engine? Do any vital TQC-related wires run in the loom on the back of the engine (which I never insulated)?

I'm about ready to go deer hunting with this thing just for the insurance money. Please save my sanity!
John Breem III

I've had problems with the connector before. The TCC wiring is in the plug that is sticking straight up on top of the tranny under the intake hose. Could also be a malfunctioning Transmission Fluid Temp sender.

Torque Converter Operation Concern: No Apply Possible Component Reference/Action


Powertrain Control System    

  · Perform Torque Converter Clutch Operation Test as described under Road Test Vehicle.

  · Electrical Inputs/Outputs, Vehicle Wiring Harnesses, Powertrain Control Module (PCM), TP, TFT, TSS Sensor, BOO Switch, TCC Solenoid, Internal Wiring Harness · Run On-Board Diagnostic. Refer to Powertrain Control/Emissions Diagnosis Manual for diagnosis. Perform Service Manual Pinpoint Tests B, C and F using the Rotunda Transmission Tester 007-00130 and Rotunda AX4N Cable and Overlay 007-00117 or equivalent as described. Service as required. Clear codes. Road Test and rerun On-Board Diagnostic.


Improper Pressures    

  · Low line pressure, low EPC pressure · Perform line pressure test as described.

    · Check pressure at line and EPC taps. Refer to Pressure Chart 401 for specifications. If low, check main control valve body.

Main Control Valve Body    

  · Bolts out of torque specification · Tighten bolts to specification.

  · Gaskets and Separator Plate—damaged, off location · Inspect gaskets. Service as required.

  · Valve Body Pilot Sleeve—damaged, misaligned. Manual Valve, Converter Regulator Valve, Main Regulator Valve, Springs, Solenoid Regulator Valve, Bypass Clutch Control Valve—stuck, damaged · Inspect. Service as required.

  · TCC Solenoid not functioning properly · Activate solenoid using Rotunda Transmission Tester 007-00130 and Rotunda AX4N Cable and Overlay 007-00117 or equivalent. If solenoid operation cannot be felt when placing hand on solenoid, replace solenoid. Inspect O-rings for damage. Service as required.

Turbine Shaft    

  · Seals—damaged, missing · Inspect for damage. Replace as required.

  · Holes—missing, plugged · Inspect for damage. Service as required.

Pump Assembly    

  · Seals, Bearing—damaged, missing · Inspect seals for damage. Service as required


  · Refer to Reference/Action · Inspect as described. Service as required

Paul N

I've been having the same issue. I changed out the temp sensor for the PCM
(worked for me in the past) and it changed nothing. When the ambient is
cool to cold, I need about 10 miles to get it to work.

I've been told here that it's the TOT sensor. Makes sense to me (not in a
rush to change it right now, coming off the road for the winter soon).
Joe Roux

IIRC, I think your issue is a little different, Joe.

Your TQC takes longer than you'd expect to lock up, but once it locks, it's not refusing to lock up again after 10 minutes, is it?

From what I see below, John's saying his TQC locks up properly when fluid temp is high enough, but then after 10 minutes, it stops locking up.

Jon Heese

True, once it does decide to go I'm usually trouble free for the day.
Joe Roux

Would that the shop actually did this much testing... C'est la vie.

In fact, the shop also told me after the fact that there is no way to know if there was anything wrong with the TQC, as it can't be opened up, and they replaced it because "that's what it seemed like it needed." Not sure what to think of that one, but this is certainly the last time I use this shop unless I need warranty work done after this is all over.

So, anyone have a part number or good source for a transmission temp sender? It's listed as a searchable part on autozone, but doesn't come up when clicking through to the vehicle search on the SHO or Windstar. Is it something that takes very little time to replace and/or test?

John Breen III

Get the Ford part from Torrie at FastPartsNetwork. If you have any electrical skills you can test it or if you have a scanner that can read it you can see what it is actually putting out.


In a hurry, so I did not have time to read really carefully, but have you tried to clean the connector yet, John?


If it wasn't so damn cold out, and the holidays weren't coming, I could just give my car to the shop for the next 4 weeks and let them figure it out (not that I trust that would happen, but still...). Getting a little tough to ride the beemer now that the snow is flying and the temps stay below freezing throughout the day.

The big honkin' connector under the MAF that's held together with a bolt? Nope, haven't tried to clean it, but DID open it a month or so ago.

Any other connectors haven't been touched by my hands. You'd think that the shop would have checked the connections, etc. when they R&R'ed the TQC, but, alas, that's too much work for some people.

Happened again today. Locked up when it reached temp, but as soon as I had to tap the brakes on the interstate, the TQC unlocked and remained unlocked for the remainder of my trip.

Throwing darts into the wind here... I'm thinking heat-related, electrical, PCM, or bad motor mounts.

I'm hoping it's not the PCM, and should probably get a hold of Torrie about a new Trans Temp Sens.

John Breen III

The tranny connector under the MAF had to be disconnected to R&R the tranny for the TC replacement.

In case you didn't know, the TC should unlock when the brakes are tapped.
Daniel J. Holtman

FYI, from my understanding, the TOT sensor may not be accessible from the outside of the transmission case.

Not 100% sure on that, and specifically in regard to the Gen3 AX4N, but it has been said about the Gen2 ATX before on the V6 list.

Jon Heese

The TFT sensor is under the side cover. It's range of output values though are the same as the IAT and the ECT.

You need to be above a certain temp after a certain amount of time depending on the starting temperature of the tranny fluid for the TC to lock up.

The scenario I'm thinking of is at normal temps it reads OK. But as it heats up then there are errors.

Indeed, with all of the TQC problems I've been having lately, I've become very familiar with what conditions should or shouldn't cause TQC lockup. I also know that releasing the brake and being back on a steady throttle should cause the TQC to lock up again, which is unfortunately not happening.

I'm hoping that Paul's assessment of a tranny temp sender, which seems totally logical, is correct, although I'm a little more than non-plussed at the idea of having paid the money I've paid for a new (reman, probably) TQC to be installed for something as simple as a temp sender.

My only consolation is that there's no telling how beaten up the TQC is after being driven for ~10,000 miles without being able to lock up consistently, so a new one would have been in order eventually.

John Breen III

I wouldn't worry about the TCs condition by being driven without being locked up. I drove like this for almost two years, including all the way to the California convention and back with mine not locking because of the final drive gear change.

If anything it reduced the wear on the TC clutch.

Now if it is a Ford TC well all bets are off.

What I would do is tap into the TFT output wire, run the wire into the cabin and monitor it with a voltmeter as you drive. I did this with the TCC solenoid power input when I had the problems.



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