Ford truck auto trans exerts??

JDEM

Well-known Member
I am at near the "end of my rope" with the trans in my truck. My main question is this. Truck is a 1994 4WD F250 turbo-diesel 7.3 IDI with an E40D trans. It there a way to unhook the lock-up torque-converter when cold? Note I already tried the most obvious approach with a simple on-off switch and no good. It winds up putting the trans into "default mode" and then have to get out my scanner and clear the codes before the trans will work right again.

I have had many issues with the trans over the years. I finally bought a remanufactured complete trans and installed it last year.
I gave up on the old one. With the old trans - after a rebuild - I stopped at a red light. Then tried to go and nothing. Just a little clunk and then no-go. Ended up a solid steel shaft had snapped right in two. After that - I was leery of metal fatigue with the old trans and bought a complete replacement.

The problem with the new trans is the converter. When temps are lower then 60 F and at first cold start - the first time the converter locks - it stays locked. It nearly pushed me through a red-light the first time it happened. Once it warms up it is fine and I can drive it all day with no issues. Next morning if it is cool out - it happens all over again. Trans is still under warranty but that only covers parts, not labor. I assume this has a defective converter and the right fix is to tear it all apart and change it. I just don't want to. If I could just find a way to turn the converter "off" until warm - it would be fine.
 
I'm not an expert but I think I would do some more diagnosis. What sensor sends a signal to lock and unlock the converter? I'd make sure that the stupid converter is getting an unlock signal before I went any farther. This makes the assumption that there is at lease two circuits controlling the converter one when it's cold and one when it's warm. Or is it the actual converter clutch sticking? Could putting some Sea Foam trans tune in it maybe clean things up enough so it behaves?
 
Was it really locked up ie you had to stall the engine to stop from being pushed or is the stall perhaps not right for your application? The unlocked torque multiplication in some TC's is really high when slipped and can be a handful.
 
What you are asking for is a "farmer fix" that will only make things worse as you have already found out.
You cannot "out think" the processor. Trying is futile. The whole system is integrated to the point that if one component does not work right, it upsets everything.
Your problem most likely one of two or three things:
Converter clutch is sticking on. The only cure for this is to replace the converter.
Converter lockup solenoid is sticking. Replacement of the solenoid would be the fix for that.

Or something is telling the converter to stay locked. Unlikely. Something at this level would set a code, light the MIL, and put the transmission into default mode.

The likeliest cause is the converter clutch is sticking. There are enough sensors and monitoring to prevent any bypassing or rigged fixes. Things were designed to work a certain way, and they must work that way to satisfy the computer's programming.
 
It is really locked. Just like coming to a stop with a manual trans and not pushing the clutch in. Add that to it only doing it when cold and the diesel engine at fast idle - it can get a little scary if not ready for it. I always am now. I just quickly throw it into neutral. Then when I put it back into DRIVE, it will stall the engine once or twice (just like popping the clutch in a manual). When it finally jars loose it works fine. I can start it, turn it off, start it again all day long and it will work fine. Next morning -if it is 60 F or colder, it happens all over again.

This truck has a computer just for the trans and I don't think it is highly complex. It gives me no error messages from these "stuck" events. When I added the shut-off switch however - it then goes into default "limp" mode and I get error 23. Code 23 means a problem with the throttle-position sensor on the injection pump and I know that is working fine. So it seems that when the converter is told to "lock" and it does not - it confuses the computer. I doubt this is an electronic issue but have no way of knowing for sure. Has a brand new solenoid pack in it and it is OEM and not el-cheapo.
 
Check trans fluid level tcc should not engage when cold , low fluid level when cold does not have enough line pressure to push converter bypass valve which is located in the pump . Add 2 qts Mercon and retry in AM , also seal on filter could be suspect and do away with your on off switch . E4od is the only ford trans that will stall engine over low fluid level
 
It could be one of three things, bad torque convertor, as you suspect, a bad selonid, or a problem with the valve body.
 
My first thoughts....Use a dpst switch with no center off. Measure the lock up coil resistance and connect a resistor of same value to the switch. The computer needs to only see this resistor when switch is flipped. I assume the resistor needs to be connected from switch terminal to ground.
 
Used to be a retired Ford automatic transmission engineer that designed the E4OD trans that posted on the OBS forum, '94 to '97 trucks on The DieselStop.Com forum. He knew those transmissions inside & out. I haven't been on that forum in the last 2-3 years but I bet he's still there. He could answer your question. Rest of these guys are guessing. I ordered my '96 F-250 out with the ZF 5-spd. 305,000 miles and it still shifts like new.
 

Find someone qualified to fix it... I have never seen a converter clutch stick but seen my fair share of TCC solenoids stick... You should have brought a OEM reman and got the 3 year 100 mile warranty are 3/36 what ever it is then at least for 3 years parts and labor would be covered.
 
Another tech where I work had a 4R100 which is next version of E4OD that the torque convertor would engage in drive at a stop but not reverse. Turned out torque convertor solenoid was sticking cold than worked fine hot. Low fluid should make convertor apply in reverse. The torque convertor solenoid is located in solenoid body assembly. If the case is warped under the main control it could cause a pressure crossover and cause a problem. Talk to who you brought it from and tell them your problem. They may send you another transmission or send you to who they have in your area to handle their repairs.
 
I've had this exact issue with a 4L60e E transmission. Never wanted to disengage the tcc when cold or hardly at all in the winter. Came up to a stop sign and it would eventually just slip the TCC. Pushed me into the ditch once when it was slippery and the abs was fighting me. Changed the tcc solenoid and all was good. If you trick it into think the brakes are on, the tcc won't engage.
 

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