Torque Converter LockUp

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ladenblowfish

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I did the 1-2 accumulator upgrade and flushed and changed over to mercon V. Now my Torque Converter won't lockup in 4th gear. Rpms are at around 2000 going 50 mph. Normally they were at about 1300-1400 at 2000 rpms. What would cause this? The fluid is full. I put in a new MLPS switch but no help. Shifts great now though. Would changing back to Mercon 3 fix this?
 
Do Not go back to Mercon 3 as it has nothing to do with your problem.

Normal 4th lock up is spec'd at 30-48 MPH with light throttle and lever in OD

at WOT it is 65-105 MPH
 
ladenblowfish said:
Would changing back to Mercon 3 fix this?
Click to expand...

NOPE...

Sounds like you might have gotten the overdrive band out of its location, as was mentioned by MrZee in the other thread.

Fluid is not going to cause nor fix your missing overdrive.

I dont think it's TC related, sounds like you actually "have no 4th gear".. AS MrZee suggested.
 
I actually do have overdrive. There is a change in RPM when I push the OD button on and off. My torque converter just isn't locking up in 4th gear. Iam positive I did nothing to the valve body or anything else other than draining all the fluid and changing the 1-2 accumulator. I'm all out of ideas. Anyone know how to fix this? Its just strange there was absolutely no problem with the tranny other than the hard 1-2 shifts before I changed the fluid. Also, this may be related but when the tranny is cold it slips in and out gear when its in reverse. When it gets warm, it fine. Any solutions, PLEASE let me know or PM me.
 
You can check the TC lockup by lightly depressing the brake(just enough to cause the brake lights to come on) while maintaining a steady cruise. The tach should show an increase in rpms when the TC unlocks.

It could be an issue with the MLPS harness connector, the TCC solenoid harness or the TCC solenoid itself.

I would pull the pan and recheck the connectors.
 
I've double checked everything. What is the TCC solenoid? Where is it located? How much replace? Is the car safe to drive with the torque converter not locking up?
 
ladenblowfish said:
I've double checked everything. What is the TCC solenoid? Where is it located? How much replace? Is the car safe to drive with the torque converter not locking up?
Click to expand...

TCC = Torque Converter Clutch

Drop your pan, towards rear of trans you will see a rectangle box with 2 "buttons", thats the shift solenoid, next to it is the TCC solenoid, square box.

Not sure of cost, call Max @ Five Star Ford 1-800-1520 ext- 236.
 
Think the TCC solenoid is my problem? If so, what would have made it stop working? Do you have to remove the valve body to replace it? What is the symptoms of a bad TCC solenoid?
 
The TCC solenoid opens/closes to allow hydraulic flow to lock/unlock the torque converter. Could be just a disturbed connection of the harness plug during the removal of the pan and the changing of the 1-2 accumulator. The internal wiring becomes very aged due to heat and can be prone to problems. You do not have to remove the valve body to replace the TCC.

The symptoms would be no torque converter lockup. You can check this...

You can check the TC lockup by lightly depressing the brake(just enough to cause the brake lights to come on) while maintaining a steady cruise. The tach should show an increase in rpms when the TC unlocks.
Click to expand...
 
Great, hopefully thats will solve my problem. Is the car ok to drive with the torque converter not locking up? Just until I can fix it?
 
ladenblowfish said:
Think the TCC solenoid is my problem? If so, what would have made it stop working? Do you have to remove the valve body to replace it? What is the symptoms of a bad TCC solenoid?
Click to expand...

Just a side note with nothing to do with this subject, but I'm glad to see you guy's actually trying to figure out problems and not just "shot gunning it" by replacing a bunch of parts and forgetting about it after it works. Just a good mindset to have because most pepole out there don’t care. Just my opinion.:D

It does sound like it’s the solenoid, but I would check the stall like stated before.
 
Problem solved! I disconnected the battery and now the torque converter locks up! The compuer must have had some codes stored :D
 
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