O/D light blinking - - comes and goes ! ? ! ?

[poolguy]

This is my 1st attempt at posting anything here, so bear with me if I sound a little too "newbie". My o/d light on the shifter of my 94 f350, IDIT, with 120k miles has gone into a blinking mode for the second time since I bought the truck a few months ago. It seems to do this after I have used the button while towing a heavy load. I have towed with it 15 to 20 times and use the button each time, but like I said, it has done this twice. I just found out by reading another post that this is the trans going into a self protection mode, but it goes away and works normally again!!! The shift when this is happening
is almost violent, and the button still works the od knockoff.
Fluid looks good, smells ok no burnt smell or taste. I've not been to the dealership, and don't really know if the local tranny shops can check these out. (Don't want to pay for a rebuild and only needed a solonoid or somethin!) I would really apreciate some help.
Thanks
Chuck

 

[Russ]

IS the tach wroking?

 

[Agnem]

Welcome to the site. I've never owned an E40D, so I don't usually comment, but I'll add that what Russ said is a known issue, and I think it likes to have a good speedometer reading too.

 

[creighta]

my 93 idi w/e40d was doing that when I got it and cleaning the tach fixed it.

My 99 dit w/ 4R100 would do that and all the gauges would go dead. It turned out to be a ford only MLPS

 

[Andrew M. Frankli]

Run the trans codes.

I had the same problem on my 93 e4OD. Turned out to be code 62 (Trans slipping). Had converter chatter under heavy load. No problem that a new HD converter and 2000 trans rebuild didn't fix. Truck pulls like a locomotive now and I treat the transmission like the fragile princess it is.

 

[poolguy]

Thanks for the replies, the tach is working, but the light is not blinking right now. Truck pulls well and there is no chatter when its operating normally. I suppose I will have to wait and see if it does it again and see if any guages are not working. I think I would have noticed if the tach or speedo were out, but I'm just not sure.
Other than this having happened twice, the truck performs quite well. I own 2 other ford diesels as well; a 99 f250 super duty ext cab w/ 130k miles, and a 2000 f350 crew cab lb dually, so I have an idea what the trans should feel like. Of the trucks, the 94 dually is the one I drive daily. Its a nice unit I bought from a member here. I just had no idea that the blinking light and hard shift were a signal to check it out! I'm truly happy you guys are out there and willing to help - -THANKS ! ! !.
Chuck

 

[Headerpower]

Pull the codes to make sure nothing is wrong, and check out the key on engine off voltage on the middle wire of the FILP/TPS. I found mine to shift early and be sluggish when the voltage was set to 1.05 at idle, so I adjusted it up to 1.2 v at idle and I get shifts more positive at higher rpms so the engine isn't lugging as much. Hard shifts may be your FILP voltage is too high!

 

[yARIC008]

Buy a code reader at walmart. They're about 30-40 bucks. Hooks up to some wires under the hood and then follow the directions and it'll give you your codes. Knowing which codes it's giving will help us narrow down the problem. My guess is just some loose connectors and worn through wires somewhere, or wires gone bad right at a connector or sensor.

 

[poolguy]

Thanks again! This time I can answer some of the questions. The tach and speedo DO work while this (blinking) is happening. I just got home from a sixty plus mile trip, and the thing started blinking and shifting hard just as I left. I have cut it off and re-started three times, and it continued the whole ride. No load, just the empty truck.
I'll check the codes tomorrow if wal-mart has the code reader.
Thanks,
Chuck

 

[Agnem]

Lots of other worthy places sell code readers too.

 

[94johnh]

Lots of other worthy places sell code readers too.

And Autozone will pull the codes for free

john

 

[creighta]

try counting the flashes (not real safe while driving). I googled my code # from an airbag light last year and found a dozen cheap fixes. . . that's also how I found this site

count the flashes, there will be a short pause and then more flashes. Next there will be a long pause and the sequence will start over.

 

[yARIC008]

try counting the flashes (not real safe while driving). I googled my code # from an airbag light last year and found a dozen cheap fixes. . . that's also how I found this site

count the flashes, there will be a short pause and then more flashes. Next there will be a long pause and the sequence will start over.

I don't think this works with the blinking overdrive light. For me it's always been a steady blinking, no pattern or anything... Maybe there is a way to get it to blink the codes, but by itself i'm pretty sure it doesn't, at least on the 92+ E4ODs.

 

[jtate]

a friend of mine has a 93 350, and it was doing the same thing with the od light flashing. turned out to be the electrical thing on the side the ip was bad (sorry dont know what the name of it is) just know it works off the movement of the ip linkage. then it did it again and was told that it was another sensor on the side of the trans that works off the shifting linkage was out of adjustment. there is supposed to be two lines that have to be lined up in either park or neutral on the sensor, and after years of movement the shift cable gets slack in it causing the lines not to line up and can cause the od light to flash.

 

[creighta]

not sure, but I think "that thing on the IP" is the tach sensor. . . the box on the trans is the MLPS (manual lever position sensor). On newer 7.3s if the MLPS goes bad it can kill all of the dash gauges too

part of why I traded my powerstroke for an IDI