You can also turn your hazard lights on if you'd rather. That also unlocks the converter. So either ride the brake pedal just a tad (just enough to make the brake lights come on is all it takes) or just hit the hazards. Either way, make sure you're driving at least 45-55 mph. The converter wont lock until around 35mph so if you're above that, driving down a flat road, your converter should be locked and either way, you should clearly see a good 200 rpm jump or more.

With that said, it's probably locking because the E40D is very code happy at setting 62 (converter slip) and you'd see the OD light flashing if it wasn't locking. Running unlocked would no doubt explain 215F @ the test port under light load with 60F ambient temps though, I would suspect. If it's locking, I dunno why she's running so warm even without an aux cooler. I guess I'd add one and see what happens but I'd still be scratching my head. I mean, I get that's she's an RV and all but still.


You know what? I think at this point I might be suspecting my sending unit and gauge. You don't have one of those point and shoot thermometers do you? They're pretty handy.

 

I don't see how putting the hazards on would send the stop signal to the PCM ... at least after 91 the hazard switch disables signal to Pin #2.

so YMMV on that deal .. Brake switch still works fine in all cases.

 

It sure isn't obvious how that happens. It even fooled the people that designed the wiring harness. But it happened. There was a change made sometime in the late '90s to fix this problem. I don't remember the exact fix or the exact time it was fixed. But the hazards did feed back into the BOO (Brake On Off) circuit and triggered the PCM to unlock the torque converter.

 

on 91 and earlier feedback happened thru the Hazard Flasher on the LT Grn wire from the Hazard switch .. in 92 the switch was re configured, that fixed the issue.

my 93 will not drop out of lockup with the Hazards on.. but it do with the brake switch enabled.... I've tested it and looked at the schematics as I was told way back that the hazards would cause this for testing lockup but it didn't work for me .... so I had to learn why

now I don't know about trucks after 94 ....... there was probably a TSB on the Issue but I have not bothered to look it up.

 

I hope that I hear the speed difference, because I have no tachometer.
I have an point and shoot Thermometer how can I use it? Outside on the tranny close the test port?

 

I tested it today and I think the TC works as you described it. nothing happens with the hazard lights.
Year of construction 91.
I'll use point shoot thermometer at the test port tomorrow. Can only measure the housing.

 

to help prevent CornFusion ... the Van wiring is a bit different from the F series that I am most familiar with... I mentioned a LT Grn wire I believe on the Van that was probably RED LT Grn.. and it looks like the dir/haz switch in the Van (at least on the 92) is configured different than on the F series...


anyway it is pretty hard to tell about Lockup without a Tach... but most likely it is working fine especially when you mention Temps drop at 50mph that is a normal function and the fact that you are not getting codes is another good indicator that it is fine.

 

The only code I get is 67 and sometimes the tranny goes to neutral and a view moments back. I think that’s the neutral switch. I only make the. Key On Engine Off test Could it be that the switch make more heat?

 

67 is MLPS out of range ....

this could be linkage not adjusted properly
Faulty MLP sensor
circuit open or grounded
Faulty ECA

it will for sure cause the transmission to not act right.

 

I can send you a PM with a troubleshoot guide if you wish.

my file is just too large to post in the Forums.

 

yes, that would be nice👍

 

PM sent, you're quite welcome

 

Pocket,
Code 67 and a trans that feels like it's neutrals out is a tell tale sign of a failed range sensor ( also known as MLPS and included internally with and often sold as; neutral safety switch). So replace that no matter what, trans temp related issue aside. This is more important than seeing 215F trans temps. Boost getting that replaced up to priority #1.

Yes, warm up the trans and take note of the gauge reading, then pull over and hold your infrared gun right up to and near the test port and the upper portion of the trans pan and see how they compare with your gauge. Did you go with a decent name brand gauge? You can expect a good 5F lower reading, perhaps 10? Not sure, maybe Mark has a better idea on that one, but I know your gun will read a little lower than inside the trans of course but the point is, it should fairly close. For example, if you see 215F on your gauge but when you pull over to shoot near the test port and sending unit and you only see F170-180 well, then there ya go. Time for a new sending unit and or gauge upgrade.
Still consider getting an aux cooler on there too just the same, even if you don't really have such high temps running empty.


Lonewolf,
my '93 F250 unlocks the converter with the hazards on. I'm not 100% on my '93 F-Super Duty (F-450) but I was pretty darn sure it does it too. I gotta run down and re-tag it and go unload it (as in empty it's bed,not part with her!) next week,so I'll try and remember to test it.

 

I can sure post the schematics of the ones know to unlock compared to the upgraded switch that does not unlock. it's very obvious why earlier had this bug and easy to see how the "Fix" was implemented by the re-configuration of the switch.... not to say that all switches are the same as you never know if aftermarket switch was used that may not have proper updates.

Not that it is a big deal anyway as most don't go cruising at highway speeds with the Hazards on in the first place. While I will agree we do have some idiots that do just that

 

now I've measured. test port display 212F and with the infrared thermometer approx. 200F. so my sensor and the display is ok.

i have a NS94T switch can I connect the wires at the same like the original. There is no manual. One pin is at both free that is for the 4x4.



marc