"To everyone that has a 90's or newer Ford with the E4od transmission.
DO NOT Run your truck with the HAZARD lights on.
By doing so will cook your transmission.
The torque converter lock up solenoid is controlled by your brake lights. Every time they flash they switch the solenoid on/off.
By doing that it ends up destroying your transmission !
Just an FYI for you Ford owners."


This was posted on another forum that I read. Wondering if there is any truth to this?

 

hmm.. that is interesting, i wonder if you have a torque converter lock up switch installed if that would keep it from locking and unlocking...

 

i have never noticed this before, i will get the converter locke dup and hit the hazzards to see what happens. i would imagine ford was bright enough to wire the hazzards into the brake light switch and not the multifunction switch

 

Me thinks that we need input from the Guru's on the validity of this.

I would not think that Ford would make this kind of Boo Boo and not issue a service correction notice.

It sounds like a wiring mod gone bad. JMHO

Rog

 

yeah, that would definatly justify a huge recall on fords part. i dont remember ever having this happen and i have driven with the hazzards on several times and never noticed anything odd going on

 

It works off the 3rd brake light.
No effect at all with the hazz on.

Bill

 

No it wouldn't. Recalls are for safety or emissions. This is neither.

It IS true. I was there when this was fixed.

What happened is that the torque covnerter unlocks with the brake lights. In the early E4ODs the PCM would see the four way flashers as a brake application. The PCM was just looking at the change in voltage on the brake light circuit and couldn't tell the difference.

The fix was in the calibration. The PCM was calibrated to ignore the brake light circuit once the TPS read more than 10% pedal.

 

Mark

About when was it changed (year).
If you run your hazz lamps the 3rd brake light will not flash with the lower(hazz). The load is not the same 4ways vs brakes.

Bill

 

Repeated for truth.

Another issue on old trucks with the flasher is that it would pulse trailer brakes too. But when the thrid brake light was added, but the transmission and the trailer brake enable both came from the third brake light circuit and neither pulse when the flashers are on.

 

I don't remember exactly, it was about '93-'96.

True, but the early E4ODs were looking at the brake light circuit. They only looked at whether it was at 0 or 12 volts. Load didn't matter.

 

This is TRUE for 1995 and 96 models. its tied into the same cicuit. I had a 95 dually that was this way and my dads 96 was this way. My current 96 is this way as well. i noticed it when I had some trailer issues and tuned them on at about 45 mph and noticed it DID unlcok the TC. I dont know if a manual lcokup switch would get you around this or not.

 

It's not the case on my '95. I wonder if your hazard switch is broken and is feeding the stop light circuit.

Here is the schematic from the '95 shop manual (click for big):



Nope, it won't. The torque converter locks up in drive. If it didn't, the TC would burn up pulling most hills.

The torque converter locks in dirve or overdirve when the throttle is depressed and the brake is off. It also locks in first or second if the revs are over 2200 RPM and the throttle is above 3/4 after a time delay - brake on or not BTW.

 

Nope, it kicks it into limp mode with hazard lights. Drive down the road in OD, click your hazards on and watch your RPMs, they WILL jump. It doesnt show it in this diagram, but it is wired in. I cant remember who posted it, or where they found it.
Do a forum search, youll find it. It was hatched out about a year or so ago on here before.

 

True. I don't think this affects the '97-up trucks. I use my flashers when approaching accidents and law enforcement traffic stops. I haven't noticed my RPMs jumping. I'll have to pay closer attention next time.

 

I know for shure it will not happen on 97 and up.
Pre 97 i cannot say. Ford did have an issue (E4OD) just dont remember when.

Bill