My '94 F-SD locks in 2nd, as did my '93 F350. I haven't noticed if the F250 does...

 

Now to throw a monkey wrench in the works - it can lock in first gear, too.

In first and second gears the torque converter can lock if the pedal is more than 75% of the way to the floor, AND the vehicle speed is high enough.

As the vehicle accelerates the speed ratio of the torque converter decreases and the torque multiplication in lost. That's when it makes sense to lock the converter, and that is what the programming does. It doesn't make any more sense to lock in third than it does in second. Once the multiplication is gone, lock it.

 

well i swear i can feel it in 2nd, 3rd and overdrive. maybe because my tranny was just rebuilt and a shift kit also added in the rebuild.

 

it's news to me also brother.iv driven my rigs just about every way imaginable and not once has either of mine locked in 2nd gear before.always right after she shifts into 3rd.i don't feel it unlock and relock between the 3-4 shift (though iv read it does,it's supposedly way too quick to feel.) when i downshift from 4 to 3 i feel it unlock and relock with ease.it will hang unlocked longer the harder i push it.

however my experience doesn't mean im implying they are or are not supposed to either.just my experience (and with the idi truck control units only too.)

 

Not to derail, in fact I think it may be of help, but I've got a little project I'm working on that may be able to provide real time answers to this. I've got the logic worked out and now need to find someone smart enough to help me build a materials list, I can do the assembly and soldering myself.

It's a few simple LEDs that would indicate which gear the trans is in and whether the Torque Converter is or isn't locked. This could be one simple LED that only indicated the status of the TC if desired. Or 5. The 1 TC status LED and 4 more LEDs, 1 for each gear. These could be put just about anywhere, I'll likely drill small holes in the dash and stack them vertically sorta like the starting lights at a drag strip, but sequencing up instead of down. But they could be put in the trim along the top of the windshield too, give something for the kiddos to watch too.

https://www.ford-trucks.com/forums/1...indicator.html

 

well its the second thing i felt when i picked my truck form the re-builder. first was a very solid feel in the drive train, then the, what i didnt understand, the double shift into 2nd, and then 3rd and lets not leave out overdrive. when i went back the following day and he test drove it, with me in it, he then explained about the convertor locking up. i know it cant lockup in first, would be able to stop at a light with out it stalling the engine, and 2nd, well really dont see the need for it, seeing as your not in 2nd for very long, but its there, i can feel it. i have read more on the fact that it does, then it doesnt, lockup in 2nd. you see i went form driving a 75 chevy with a 454 and the big smg645 tranny, the one with the granny low, which i out 300,000 miles on, to my F150 with the E4OD. so it was a difference to say the least. cant really remember what my F150 shifted like, just that it had AC and it was 110 degrees outside. seem to shift smooth, it had 100,000 miles on it. but everything points to the fact that it shifts then the convertor locks up, then unlocks, shifts then locks up, and so on and so on. like i said i cant remember how exactly it shifted but i was getting 16.5 mpg so i dont think it was slipping and it seems if it wasnt locking up then i wouldnt of been getting that mpg. how it changed took 100,000 miles and came on slowly. im going along with what Lead Head stated. 1s,t 2nd, 2nd lockup, 3rd, 3rd lockup, overdrive, overdrive lockup. thats good enough for me.

 

i thought i had to much free time. LeoJr you have a good idea, and it would be fun to do. ofcourse a light indicating that the convertor is locked up isnt going to actually mean its locked up, just that its suppose to be. but it would be something to do.

 

well have some more free time on my hands so been thinking about this lockup again, and it still feels different to me when it changes into 2nd and 3rd, like a shift then a grab, dont feel anything in overdrive. shop did install some type of shift kit, not sure which type. im going to call ford monday to see if they can diagnosis it. they should have the equipment to tell me if its right or if something is wrong. could just be that it gradually lost it grab and i really didnt notice iit, and now its all new. wishful thinking.

 

Sorry, but no Ford dealer is still going to have equipment to diagnose OBS EEC-IV trucks with E4ODs. That stuff was thrown out years ago.

You have a brand new converter, with a rebuilt transmission. I already told you that the E4OD works by unlocking the converter, shifting, then re-locking it.

The early E4OD that came in your truck had many flaws, including a pump that couldn't pump enough fluid, numerous valve body issues, clutch issues, torque converter issues and many other internal problems.

The way to rebuild an old E4OD is basically to throw everything away and put the 96-97 E4OD stuff inside of it. It's going to feel different.

 

yeah ok, must be a paranoid thing left over from Vietnam. im sure they did a hood job.

 

Thanks for the info Mark!

 

Mark Kovalsky, best explanation of the torque convertor workings.

 

Unlocking during the shift makes sense. And I can see how trying to lock it back up after a gear change works the clutch.

Is there an affordable TC upgrade that isn't $1,500 to $2,000?