Hey, guys. I have a quick torque converter question. I have a '92 F-250, 351W, E4OD. When I come to a stop the engine dies. I know it is the torque converter clutch staying engaged. I do have a TCC code stored. I'm wondering if there is a way to disconnect the TCC so it never goes into lock-up, since it only seems to happen after I've reached higher speeds and it goes into lock-up. I thought maybe a wire from the PCM to disconnect? I have All-data access, but it doesn't have wiring diagrams for the trans. Anyone know which wire, color and pin number, and if this will work? I know it's not the proper repair, but I have $17 into this truck, it's pretty rotted, and I'm just looking to get by until spring. I don't drive much, but occasionally I need to get somewhere. Thanks guys.

 

I have seen posts where people added a switch in that circuit so they could manually control TQ lockup. (keep it from locking, not make it lockup). One person said it didnt even kick a soft code. I have been thinking of doing that myself and have looked at the wiring on my 93 EVTM for my Bronco.

The leed that controls the TCC from the PCM is a P/Y (Purple/Yellow). The easiest access to that leed is in C103 which is one of 2 connectors that are part of one harness from the tranny. The other is C110 and they both are located on top of the drivers wheel housing, just under the front of the master cylinder. Those 2 connectors carry most of the wires to the solenoids in the pack in the tranny. C103 is supposed to be a black, 4 pin connector and C110 is supposed to be a black, 8 pin connector, Let me check though, because it seems the pin count is not correct in the EVTM. I think I did some earlier checking and found more circuits that feed through the 103/110. Other colors in C103 are: O/BK, BR/O. C110--P/O, O/Y, W/Y, W/R.

This EVTM is for 93, but I would bet KB's next paycheck the colors and connectors are the same.

 

Sorry for the double-----I meant to ask you if the tranny acts like a manual tranny without the clutch released when stopped. Before going to any trouble to cut wires and mutilate the harness, check around the connectors and the harness and also down at the tranny plug to see if any of the leeds are pinched (numerous times people have found crushed harnesses after tranny work was done. The PCM switches the GRD to the solenoids to pull them up. It may be that a skinned insulation on the TCC wire is crossed with something else or even is pinched to some framework. The 12 VDC is a common feed to all the solenoids, directly from a fuse through the PCM power relay, which is pulled up in either Start or Run. That is the Red leed in C110 along with the W/R for the EPC.

 

you could also just unplug the TCC solenoid plug and leave it like that.. we did it on an old cutlass of mine for yrs... the solenoid was bad on it... and whenever ya tried to stop it wouldnt disengage.. (matter fact it would try and tear the tranny up for that very reason)... so we simply unpluged it and left it like that for yrs... car drove fine without it and were still getting 32mpg from it..

 

The E4OD TCC solenoid does not have a separate plug to disconnect it. If you unplug the connector its in, the TOT sensor, and the CCS will also not work. I am not sure he is trying to eliminate lockup totally, just resolve the immediate problem. If there is a shorted wire in the harness or it is touching a ground somewhere, then it will not do any good to cut the wire, it may be shorted at the tranny. I suggest not screwing up a harness that might just work until you determine where the problem is. Since this vehicle is a cheapie, you might try cutting the wire, or removing the pin at the connector. Whatever you think best, but realize that it still may lockup. Also, it is more efficient on fuel with the converter locked up----if thats any consideration at all.

 

darn.. sorry mate... guess my suggestion wont work then..

 

The E4OD is designed to work with a locking converter. If you manually disable the TCC lockup circuit, two things will happen: One, the tranny will not like the extra heat generated by the slipping converter. It may lead to failure of the converter, the trans, or both. Two, the computer will notice that the lockup isn't working and it will throw a CEL and put the tranny into limp mode where every shift is very hard.

I would advise not cutting the wire or disabling the lockup circuit. Try to find out why it's not disengaging first. If you put the tranny in neutral as you come to a stop, does the engine stay running?

 

I agree with what you say except the computer. If a guy is determined to do it it is possible to wire a resistor into the circuit to fool the computer.

 

I understand the extra heat created by a slipping converter. I am curious why it would creat any more heat than a converter without lockup capabilities. Certainly you need more tranny cooler, but why would it be any more than a C6/C4/FMX etc. The stall speeds are about the same (variable). I would really like to hear a tranny expert (I am not) enlighten us. On the AOD/4R70W, for example, it is common to put a 1-piece input shaft coupled with a regular converter with its regular stall (I did it on a 90 stang).

I have lots of experience in electrical circuits and have figured a way to use a switch that will disconnect the TCC leed and place a resistor in the circuit so the PCM will see a termination for that solenoid. I think the PCM uses sensors to determine what the expected input/outputs are. If not expected, it kicks out the code. Several people have posted that it does not cause "limp home". Why would it? If the TC clutches are slipping (commom problem) the PCM blinks the light on the stalk, maybe kicks a code, but does not cause limp home.

First thing next monday, I will try it on my bronco. If not then, the next monday, If not then---------

 

benshere,

The torque converter is doing exactly that... acting like a manual with the clutch engaged. The engine will keep running if I go to neutral, but the torque converter will still not disengage, so it will die when I go back to drive. The only way to fix it is to shut it off and restart it. I'm sure it's either a bad solenoid of converter, since it is a problem that I noticed get worse over time. It for a while would hang up a bit, I'd feel the rpms drop and it almost die, and then last second it would disengage and keep it from stalling. Then as time progressed, it started stalling intermittently. Now, every time it goes into lock-up beyond 30mph or so, it will not disengage. I'm perfectly ok with completely eliminating lock-up. I don't drive much, and the trans has an aux trans cooler to help a bit anyway. Thank you for the info on the wire/connector. Without a wiring diagram, I'd be looking forever! I'll give it a shot disconnecting it and see what happens. I know there has been trans work in the past, so if it doesn't work, I'll check the harness like you said. Thanks for the information!

 

I found this in some info I had stored on my computer, I have never seen it happen but who knows.


If you have an E40D transmission that is killing
the engine when you put it in gear, see if the
filter was loose and dropped into the pan.
This condition results when a loose filter doesn’t
allow the pump to pickup enough fluid to hold
the converter clutch “off”. With low pressure on
the release side of the clutch piston, fluid already
in the converter tends to push the clutch piston
“on”. This will kill the engine when you select
Reverse or Drive.
The fix is easy. Ford added three legs to the
filter. These legs keep the filter in place. The
updated filter (Ford part # F6TZ-7A098-AB for
2WD and Ford part # F6TZ-7A098-BB for 4WD)
is available from your local Ford dealer.

 

jk080,

Thanks for the info. I've never had it happen unless I've reached higher speeds and then slowed down. Do you think that the filter is still a possibility? I know trans work has been done, but it was before I owned the truck, so I don't know what or where it was done. Also, could that possibly cause strange shift patterns? Shifts seem to be intermittent, and shift points tend to vary quite a bit. Example, sometimes I have to reach speeds of nearly 70mph before it will go into overdrive. Other times it will shift in at under 40mph. I know throttle pressure has some say in that, but that's just when I'm cruising. 3rd seems to shift very early, sometimes 15mph. I can tell the engine rpms go pretty low. My other car is an '85 Capri with a 5 speed, so I have a good feel for engine speed. I can tell the shift is too early. I haven't been too concerned because again, it is a cheap truck and as long as I press the pedal on the right and it moves forward, I'm pretty satisfied, lol!

benshere,

I disconnected the purple/yellow wire. The harness and connectors were easy to find, just like you described. I pulled the terminal out of the connector so it can easily be put back in later. I don't think it was the correct wire, though. I no longer have reverse lights, and that's all I can tell has changed. It still goes into lock-up. Makes me think there must be a change in wire colors from 92 to 93. Do you possibly have a way of describing the pin location? Maybe use the locking tab as a "top" reference and looking into the transmission side connector when the connector is apart... I don't know if you even have that info. I thought about disconnecting one wire at a time to see if I can figure out which on it is. There are only about a dozen and I'd imagine half or so of them should be a quick obvious "not it" condition, right? lol! Anyway, thanks for you help so far.

 

The plot thickens Hold that thought and let me dig out the EVTM again! That P/Y certainly should have no effect on the reverse lights. I am beginning to wonder about another problem with the MLPS, given the erratic shifting

I will have to looksee if the PCM turns on the lights when it detects Reverse from the MLPS, or if it is a strictly mechanical switching. Could very well be a difference in colors between 92 & 93, but I really doubt it. Most, if not all the wires in those 2 connectors have to do with the tranny, will have to try to run down any other wires.
BTW, you sure you didnt do what I did the first time I was looking at the connectors/wires that is call P pink instead of purple?

 

Looking--looking The backup lamps are controlled manually, through the MLPS when in Reverse. You need to check the colors carefully in the connector. It looks like you may have pulled a P/O (Purple/Orange), which feeds 12V (circuit 298) through the MLPS to the backup lamp circuit (also to trailer tow circuitry if equipped). Take some hand cleaner and an old toothbrush and clean the wires at the connectors where you can fan them out to look. The TCC lockup is a P/Y (Purple/Yellow), easy to mistake the Orange and Yellow tracers.

Have to get another cup and look into more wires (leeds) in those connectors. There is an alignment procedure for the MLPS on the tranny, similar to the procedure for aligning shifters on a manual tranny. Prob use a drill bit to locate and set the center position. LOL

 

benshere,

I double checked which wire I had disconnected. It was purple, and the tracer really did look yellow to me. When I checked the rest, I found another purple wire, and it looked like it was a white tracer. It was slightly off-white or cream colored, so I figured it may just be faded. Anyway, I disconnected it and it was indeed the correct wire, which leads me to believe that somehow the wire colors have faded over the years. I wouldn't expect it to, especially under the hood, but there is evidence of an old brake fluid leak from the master cylinder that must have been repaired in the past, so who knows. Could be my eyes failing me as well, lol! So I drove it and it drives much better in every way. Shifts seem smoother. It still shifts into third early, but without torque converter lock-up, it isn't quite as noticable. I noticed that the trans would seem to have somewhat of what I would describe as a hiccup. It seemed like a very quick flare and then a harsh bang immediately after. This was before the torque converter disabling. I've driven it for over an hour today and have not felt it once, which makes me think that there for sure was a problem with that lock up clutch. Anyway, my truck is running strong and driving pretty well for its age. Just want to say thank you for your help. Hopefully I'll have a relatively problem free winter.

Thanks again,

Jason