2001 torque converter clutch not disengaging

[j---]

TEMP FIX 2001 torque converter clutch not disengaging

Good morning. I have a 2001 eddy v6 4wd explorer. 202,000 mi.

This has been an intermitted problem for years, mainly being only four or five times a year until recently. It wasn't until about a month ago I even suspected it being transmission related. However it has gotten to the point where now the tcc will not disengage at all unless I put it in reverse for about ten seconds or so. The fluid is within specs and is a very light color, it was last change less than a year ago. I do not hear any abnormal noise from the torque converter or anywhere else for that matter. Drives just fine other than it stalls when I come to a stop, much like when the clutch is in on a standard transmission. It didn't cause the Check engine light to come on until the other day when the problem became constant. I do not have access to a scanner for awhile as I don't live near a city and the local parts shop doesn't have one. I may know someone who has one and might get it scanned in a few days, otherwise I'll have to solve this problem the old fashioned way.

I suspect this is either the TCC solenoid or the valve it connects to. Do you folks agree? My shop manual is a Haynes and doesn't even talk about these parts. I looked here on the forum and saw how to replace the solenoid from a 2002 explorer, seems easy. But is it the same for a 2001? Seems there are a bit of differences in the two. Also, I have found replacement parts for the solenoid but can not find replacement parts anywhere for the valve. Where can I get a replacement valve if I end up needed one?

Thank you for any help.

Jeff

 

[j---]

or does anyone think it might be a sensor, since I can get the clutch engaged by putting it in reverse? And if so what one?

 

[Macgiobuin]

Since your engine stalls when you come to a stop, for sure the torque converter lockup is definitely engaged. It can be stuck for 2 reasons: electrical or mechanical. Electrical: Torque converter clutch solenoid is activated when the PCM grounds its dedicated circuit; if this wire (violet with yellow stripe) that goes to the PCM (pin #54 ) is chafed and/or grounded to a ground wire or the frame, it will keep the solenoid activated and the torque converter locked. How to diagnose? use an ohmmeter to read the TCC wire between the PCM connector and ground, and if it's grounded, you probably found the problem, trace the wire and fix it. Mechanical: The TCC is stuck on and deactivating it has no effect. Take it out and do a bench test, applying 12v to both tabs. If it isn't clicking, or only clicking some of the time, it's bad. If it's clicking good, then the valve in the valve body may be hung up because the valve body or the modulator valve itself is warped. You can fix the valve by making sure it's straight, and by chamfering the sharp edges. The TCC solenoid is on the group of 4, the small one on the end. It is accessible by taking down the pan, and the solenoid bracket holding the 4 solenoids, extracting the TCC solenoid, and the modulator valve may pop right out.

 

[j---]

Thank you for your response. With the good weather, I think I will start on this this weekend. I am just wondering why the clutch disengages when I put it in reverse. Does putting it in reverse put a different pressure on the solenoid helping it retract?

Honestly, this is the first time I have really looked into how this or any electronic transmission works. Learning a lot with this problem.

 

[Macgiobuin]

It's either the hydraulic shock of applying the low/reverse band, the reverse clutch, and shift solenoid 1, OR it's the rotational shock of the transmission case itself breaking apart a chafed wire from its unintentional grounding.

 

[Robman]

TCC Modulator Valve (37947-07K):
A TCC modulator valve that will not stroke or may have partial stroke can be diagnosed on a road test. The SonnaFlow® must be installed and converter fluid must reach 150 degrees Fahrenheit before the thermal element opens, allowing for external cooler flow. Flow will increase from an average of 1.4 GPM with TCC off, to 2.3 GPM-plus under full apply. The scanner should be used during this drive to monitor TCC duty cycle percentage. As modulation increases to 50%, the solenoid should have fully stroked the TCC modulator valve. When you see the sharp rise in GPM on the SonnaFlow®, the valve has fully stroked. If cooler flow does not rise as TCC apply is commanded or the engine stalls upon forward engagement, inspect the TCC solenoid first. If the engine stalls forward and reverse, look for blown gaskets, a worn pressure regulator bore (which you can replace with 37947-05K) and then pump or converter issues.


I read that somewhere.. ^ pertains to 4r/5r55e

 

[2000StreetRod]

brake pedal position switch?

The brake pedal position switch (BPPS) notifies the PCM when the vehicle is stopping. It can easily be checked by engaging cruise control and then tapping the brake pedal. If cruise control disengages then the BPPS is functional.

 

[j---]

That makes sense Macgiobuin. I did test the brake pedal position switch a couple days ago using that same method. Checked good, disengaging with very little pressure. I will start on the tests this afternoon if I can and get replacement parts if needed in the mail as soon as I can.

 

[~X~]

The brake pedal position switch (BPPS) notifies the PCM when the vehicle is stopping. It can easily be checked by engaging cruise control and then tapping the brake pedal. If cruise control disengages then the BPPS is functional.

I still haven't found the real reason mine was doing the same thing. It shifts fine now, really good actually, but I have a feeling the rollers from my disintegrated thrust bearing were getting into the old valve body. I found them on top of the separator plate gasket and in my filter, never did pull the old solenoids to see if they got into them though. Still looking for a core transmission to rebuild.

Anyhow: http://www.explorerforum.com/forums/showthread.php?t=437084

 

[45Frank]

This must be a common thing. I had a 2000 I bought new that did this the entire time I had it. Three Ford dealerships and never did fix it. Finally after 6-7 years (Under Warranty) had to trade it in. I did have other electrical problems with the vehicle the entire time also, door locks would lock for no reason, blinkers would stop working, windows would stop working, radio wouldn't work sometime and a few other things I don't remember. Spent probably more then a year in the shop the time I had it. Funny thing was the only thing they ever did all that time was the head gaskets and I never brought it in for that. LOL go figure!
Good luck.

 

[j---]

How to bench test the solenoid? Macgiobuin says to apply 12 volts to both tabs. it the body or the bracket the ground? Or am i misunderstanding?

 

[Macgiobuin]

The body of the TCC solenoid (any of these solenoids) is not electrically active. There are 2 electronic tabs on the solenoid itself. Although it does not matter which tab you use for + and -, the in site design is that the light blue/orange wire flows the positive current, and the violet/yellow is the ground connection that goes to the PCM. Because the solenoid is an electromagnet that moves in only one direction when activated, it does not matter on a bench test which tab is tested +. There is not a diode in the solenoid.

 

[j---]

Thank you. I wanted to make sure I did it right and not screw up something. So I tested the connecter that plugs into the solenoid against the transmission case. The one side with the purple wire showed no change, read a 1. The side with the black wire did show a change, assuming this is the ground wire and is good. I ran out of time and didn't get the valve out. Will need something to pull it out. I did push it in and it seemed to slide back ok, but will pull it out tomorrow to really look at it.

The solenoid had a resistance of 11 ohms. That seems to be in specs. When applied power it clicked every time. So it looks like the solenoid and wiring are in good shape. Hopefully I will find the valve all bent up or I'm back to square one. I also replaced the crankshaft sensor the other day. The part was only 13 dollars and cheaper than 4 or 5 quarts of ATF.

 

[j---]

The valve looks straight. I've checked everything mentioned here I believe. For fun I checked the big solenoid, read 5 ohms. Not sure if that is in specs or not. I lightly sanded the edged of the valve with 400 grit to take the edge off to help prevent sticking. However, pushing the valve in with my finger it seems to go in and out smoothly.

When testing the solenoid it only clicks. Nothing protrudes out. Shouldn't the solenoid protrude out when given power?

 

[j---]

fixed temporarily. Since last post I have done nothing else, but last week we needed the rig for an upcoming snow storm. So I buttoned everything up and added fluid. took it for a drive and the problem did not occur. In fact after several drive the problem did not occur once. Unfortunately I do not have the satisfaction of repairing anything. So that leaves me with speculation. I'm guessing that 1. an electric component had some static built up and unplugging one of the connectors released that build up 2. the valve was sticking and sanding the sharp edges worked. 3. maybe a clog in the valve somewhere and draining the fluid or playing with the valve broke it loose. 4 or I bumped something and temporary fixed it somehow.

With not knowing the fix, I can only get my hopes up on this being a temporary fix and may see this problem arise again. But with 202,000 this rig has been very reliable.

 

[alohamonte]

If you're going to replace one solenoid, you might as well replace the entire valve body (with all new solenoids).

 

[j---]

I didn't replace any solenoids. I don't want to replace the whole valve body. Not while everything is working.