I was typing and thinking (a slow process), while you posted LCAM. So I asked some questions that you addressed. Thanks!

Well, I am somewhat relieved that it doesn't sound like my converter, though electrical troubleshooting for finding some override is not my forte either. There are some toggle switches on the dash that I have no idea what they do (or if they are connected). I also have a couple wires that were originally hooked directly to the battery that aren't anymore. I thought it was likely a stereo as one has an inline fuse. Maybe one of those (toggle or hot wires) could be related to converter locking? Obviously don't expect an anwer whether they are it or not, but more whether they are potential culprits. At some point I need to find out what those switches and wires are for, but I am doing triage at the moment...... Going hunting this weekend and already have a thermostat to install.

 

"I have a 94 F250 4X4 7.3 IDI factory turbo, 4EOD, and 4.10 gears."

you have mistakenly purchased the wrong vehicle for your usage.
see 4.10 axle ratio's are a low,powerful "towing" gear.
not only do they multiply pulling power,but they will increase your rpms.
rolling down hill becomes slower as well,because they will actually hold you back.

there's a couple things to do now.

1.sell the truck and buy another with 3.55 gearing (usually not practical.)
2.swap the rear axle for one with 3.55's and have a shop install new gears in the front to match.
3.have a shop swap out front and rear gears.
4.install taller tires thus increasing your gear ratio.

even with my 3.55's and 29" tires giving me a 3.84.1 i also slow down rolling down long grades,unless im loaded up heavy i need to give her a little throttle to maintain 45/50 mph as well.

lets say you did what Dave did.he installed 3.08 gears,because he drives over the road long distances at freeway speeds most often.with his gears (and i think he even went taller than stock tires) he likely actually picks up speed rolling down hills.
3.55 and 31" in my last truck,and i needed a little brakes to slow me down to maintain the speed limit too.

 

Dually-convert (hope you don't get pissed for me calling ya that), his issue ain't got nothing to do with gears, and everything to do with the transmission - I got 4.10s as well, and when I unlock the converter even when empty she starts rolling downhill like it's going outta style

Definitely sounds like the converter is staying locked, mine does the same when I have the switch for it engaged. Do try the brake test tho, this may shed some light on the issue...

As it was explained to me by a former Ford transmission engineer who worked on the E4ODs, if the coast clutch was to apply while the transmission is in 4th gear (OD), some major binding will occur between moving parts resulting in serious damage. This was his answer to my question of whether it's beneficial or even possible to force the coast clutch to stay applied every time the converter is locked - it's possible to wire it up this way yes, but I will damage my transmission if I did.

Indeed methinks there's nothing wrong with your torque converter itself - something has been altered in its management setup tho, something that overrides the PCM's factory logic of unlocking the converter at off-throttle. Could it be one of those switches on the dash provides an alternate circuit for the converter solenoid ground (that's how the converter gets locked, by grounding its solenoid) - I'd say so, but then again whatever said switch controls is also able to see what speed the truck is moving at - if it weren't speed sensitive then it would keep the converter locked all the time, which would kill it very quick. The more I think of it the more it seems like there is some aftermarket module at play here, unfortunately my experience with these is zero, so I dunno what to look for or where to look for it... I can suggest that you crawl under the truck and trace the solenoid pack harness from the transmission up towards the PCM - the solenoid pack connector is on the passenger-side of the transmission behind a small metal heat shield, so locate that and start from there - the harness should go from the transmission to the driver-side frame rail, then along the frame rail to under the cab firewall, then it goes up along the inner fender and splits into three connectors (IIRC they are green, white, and black in color). Past the connectors it may join into one fat harness again, I'm not too sure on that are for your bodystyle of trucks... If you see nothing spliced in the harness along its route from the trans to the PCM, no shiny boxes with electrical connectors and such, then you may have a re-flashed PCM, or a programming module plugged into the PCM itself - hell if I know if someone even offered this, but it could be possible...

 

lmao.nope i don't mind that.
hmm.i'll be watching this thread myself then.cus im not rolling down hill with ease.unlike the op,im seeing my rpms drop though when i let off the skinny.but i require some juice to help me down grades.not steep hills,but long easy hills,where my car would be going well over the speed limit if i didn't hold it back.

rolling down hill fast and 20 mpg(as per other threads.) are you sure your running 4.10's LCAM? lol.
maybe i could use this manual tc switch mod more than i thought.-not sarcasm.

 

Thanks again for the advise, LCAM. It's dark now, but I might still try to get out there tonight with a flashlight and see if anything jumps out at me. I can probably get away for a quick drive to do the brake tap with throttle on test just to see what it does.

FORDF250HDXLT, I would agree that maybe it's not the "ideal truck" for my "needs", but sometimes where desire intersects budget and availability, you're not all that close to desire. I think with a little work, she'll do me just fine. In my price range, I was seeing plenty of F150s with 150,000+ and then this came up with 144,000 with the benefit of being a diesel. Didn't seem like much of a choice to me. Anyway, I digress.... Tires are on the list, gears are on the "maybe" list, Swapping her out for another completely......might have to get back to you on that depending on what else I find!

Sounds like the toggle switches are possible, but unlikely (unless they're wired to the speedo, and even then not probable). Also sounds like an override of the factory PCM would have likely already displayed some other adverse effects (like completely kaput transmission). I will see if I can find anything that looks like an add on and see if I can find some sort of identification on it.

Appreciate the help!

 

Now now, play nice - it's 20 mph cruising on the interstate at 1900 rpms, over several hundred miles distance - and actually I hardly ever unlock the converter, usually once I'm up to speed I lock her and then hit the cruise and she drives herself with very little input on my part. For her to want to pick up speed on her own with me off the throttle the hill needs to be at lest 6% but anything less than that can hardly be called a hill to begin with - and sure on the way up she'll drink the fuel like nobody's business, but then on the way down when I back off the throttle all the way she sips it at the rate of a gallon an hour or so (1 gallon every 3 hours at 700 rpms idle equals to 1 gallon every hour at 2100 rpms idle) so if I'm rolling down at 60 mph that puts me at 60mpg instantaneous till I hit the bottom of the hill or have to step on the throttle again for whatever reason.

The manual converter switch actually don't help me in this department, matter of fact you should be better off than me as when we both let off the throttle your engine returns to its idle speed and low fuel consumption, while mine drops the fuel delivery rate to idle specs but cause I'm turning so much faster I'm still burning more fuel than you. On the other hand I don't have a big flat wall behind my cab like you do, unless I got the camper loaded up, at which point the truck's weight jumps up by over a ton and aerodynamic resistance area about doubles and all fuel economy bets are off - 14-15 mpg cruising at 1900 rpms, if I have to climb hills it probably drops to like 4-5 mpg, on the way down tho that converter lockup is a blessing

 

Oh, by the way, Dinosaur-Bones, did you know that coasting in neutral downhill is actually illegal in many states? Nevermind the whole Georgia overdrive thing, them folks are idiots for pushing their luck like that, always keep her in gear even if does cost you some speed and fuel economy - god forbid one day your brakes go out for whatever reason, you'll be glad that you had the trans in gear, even tho slushboxes ain't anywhere near as bad as bolt-actions when it comes to speed-shifting her into gear...

 

I didn't think to look whether coasting in neutral is illegal.... Sounds like it's a bad idea regardless.

Well, I took her for a drive to see if anything else provided a clue. So, I was not entirely accurate about how it's behaving, though it still doesn't seem right. 1st through 3rd gear, when I let off the gas, it immediately returns to idle and has that coasting feel. In OD, it does drop about 300 RPM (2,000 to 1,700) roughly, and can feel the engine slowing me down.

I also tried tapping the brake lightly with throttle steady, and there is a slight momentary increase (seemed about 100 RMP increase). I don't have any long grades close by to see how long it takes to get all the way down to idle and whether I would be at the equivilent speed as OD at that RPM. The freeway still had enough traffic that I didn't let my speed drop below about 45 mph, but still had that feel like more than wind resistance was slowing me down.

Also would have liked to see if starting from stop on a long, steep grade whether I could just keep my foot off the gas, let gravity take over and see how the shifting feels. I might be able to try that next weekend on a long grade with little traffic.

I did see the wiring you mentioned, but in the dark, didn't track it all the way up. No splices right by the transmission.

 

Found this in another thread (https://www.ford-trucks.com/forums/9...nner-help.html).......

Power onthe brake circuit unlocks the torque converter.
It don't take much power on the brake circuit to unlock it either.
A bad ground in a tail light or trailer wiring are very common locations for power to get backfed into the brake circuit.
A problem in the turn signal switch in the steering column can also cause your problem.
Tracking it down, will probably take some hair pulling though.
When someone has a problem like this, I always recommend checking any wiring that was not stock first.
Then move on to things like grounds that were stock, and may have been disconnected either on purpose or by corrosion. - Dave Sponaugle

Any chance there might be a relation to my issue? I do have a trailer brake (don't know if it's connected or works), and definitely have some non-stock sloppy wiring. Trailer wiring is spliced a few times, and looks really sloppy. I dunno, seems like it would happen in all gears (not just OD) if it was faulty wiring.

 

Nah, I don't think that's what you're working with - what Dave was referring to is the converter staying unlocked when it should lock up, you have the opposite situation. Did you find anything on the transmission wiring that looked non-factory in the daylight?

 

I was thinking about this thread last night on my way to and from the airport. I had lots of highway and secondary roads all to myself, so I did some experimenting on my truck.

At low speeds, when I let off the throttle the RPM's drop to idle. The truck is coasting.

At highway speeds, when I let up the RPM's don't change.

Idling down a grade from a stop, as the truck gains speed the transmission gradually started engaging the engine.

I reread the first couple posts here, and I don't think the OP's transmission is acting any differently than mine. I am all stock.

Thoughts??

 

The torque converter stays engaged due to fluid pressure on the stator, it has nothing to do with lockup. This exact same thing happens with a C6, which has never had a lockup clutch in the converter, so stop worrying about the converter being in lockup... As to the fuel mileage, the lever for increasing the fuel is at the idle setting, so the fuel delivery will be the same as at idle, no matter what the speed of the engine. If you are disengaging the trans, you must be riding your brakes all the way down to hold your speed back. So which do you think is worse, using a little fuel (which you don't) or burning up your brakes on a steep grade, causing potential failure? You need to be using the engine braking of the motor to help keep your speed reasonable on steep slopes.

 

Thanks for adding some more to the thread. I had a pretty busy night last night before I got to the truck, and then spent most of my time flushing the coolant system and installing a new thermostat, so I didn't check the wiring LCAM....

Anyway, I have been thinking more and more that maybe I'm just paranoid, and maybe it's normal. Fellro86, your point makes sense, because it doesn't feel like it's fully locked, but does provide some resistance. It sure would make sense to have it set up that way for towing.

It would be nice to have others also let me know I'm worried about nothing. I'm new to the truck (and diesels) and won't be hurt by being "the dumb guy". Thanks!

 

Posts #9, 10, and especially #27 are spot on. There is nothing wrong with your trans. At highway speeds you should have a little engine breaking.
Like others said, If your vehicle is in motion you have to have it in gear, for yours and others safety.

 

The factory E4OD torque converter is a pretty darn loose thing, it allows for about 500 rpms difference between engine speed and transmission input shaft speed - this helps get heavy loads moving cause of the overly high gearing in the trans (seriously, a 2.18 reverse, that's boderline useless when you're hooked up to something near your max GCWVR), and when you're cruising the lockup clutch is engaged to reduce converter slip and heat generation and at the same time improve fuel economy, so you get the best of both worlds in a sense. What these guys said still true, however when you let off the throttle your engine speed should drop some, in case of coastng down a steep hill it would not be surprising to see the whole 500 rpms difference on the tach. So if the vehicle speed can be maintained at 1200 rpms in OD then when the converter unlocks the tach may read close to idle, now if the vehicle speed would require 2000 rpms in OD to maintain then when the lockup disengages the engine speed will only drop down to 1400-1500 or so and there will obviously be some engine braking. However if I'm understanding the OP correctly and I'm not missing anything in the process he actually sees is no engine speed whatsoever when he lets off the throttle - he said it post #15 that it's like a stick-shift when you let off the throttle without pushing the clutch in, this is exactly how a locked converter behaves at off throttle and nothing like how it should behave when it's unlocked and allowed to "freewheel" (within the limits of its slip capabilities of course, those 500 rpms I mentioned above)...

I don't think this is correct - the throttle lever and the governor it controls regulate the amount of fuel the plungers deliver per their stroke, and at idle there are only so many strokes per minute (not sure how many strokes per crank revolution, I'd imagine it's one stroke since the IP turns at half the crankshaft speed but there are two plungers inside it) - however when the engine is being "forced" by the rest of the driveline to turn faster there are now more crank revolutions per minute and therefore more plunger strokes per minute, resulting in higher fuel consumption that just idling while standing still and not moving at any decent rate of speed, even tho the fuel delivery amount per plunger stroke hasn't changed... Makes sense?