# Blinking overdrive light



## Shack (Dec 5, 2000)

I have a 94 F350 diesel. The overdrive light will blink off and on while sitting at the red light from time to time.
Have any ideas?


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## SLSNursery (Dec 21, 1999)

*Tranny time*

Take it to a dealer so they can diagnose the problem, which will most likely be that the transmission is shot. See if they can help you at all since the truck is out of warranty (they helped me greatly with a 97). If you let it go too long the dealer told me that debris from the bad parts can get tangled up in the cooling system (might need new radiator).

Or, if you want to, do like a friend of mine - same thing with his 93, he disconnected the battery overnight to reset the computer, then drove it until it broke totally.


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## Cleve (Dec 23, 2000)

I believe that before doing much of anything else I would completely drain the trans and the TC, fill with Mobil 1 ATF and change the filter. Will cost you about $75--$100 but might make the difference. Also like the idea of "resetting" the computer. Although I don't think you have to wait overnight. Just 30 min.or so. The truck will also drive a little differently for a few miles after that. 
You might want to add a better cooler for the trans also. The factory one is not adequate for most loads. Sitting at lights might add a little more heat to the unit.
Even if it was new, all the above would be good for it.
Cleve....


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## John DiMartino (Jan 22, 2000)

It could be something as little as a bad solenoid or a loose wire,if you want to service it,and take it in and let a pro look at it.


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## nlminc (Jan 3, 2000)

I had the same problem with my 97 350 ps diesel. Ford replaced the Torgue Converter, the Darm Reman Conv Asy-trans for a fee of $586.77. They told me it was not covered under warr. cause this part is not in the drive train system. 

Chris


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## John DiMartino (Jan 22, 2000)

Torque convertor is a problem on Fords,especiall yif you dont service your auto every 15K if you tow/plow or 30K otherwise.The torque converttor is covered under the 3/36,and is part of the powertrain,it would be covered under any powertrain extended warranty also,provided ou serviced it at recommended intervals.


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## plowking35 (Dec 21, 1999)

In fact ford still has issues with auto trannies, they just recently had to halt production of all gas powered trucks due to a diode failure in the trannies. Diesel powered trucks were not affected because the faulure would only occur after full throttle above 4700 rpm let completely off the throttle and then back to full throttle. I am not picking on fords but read the article from dearborn news or something to the like. I will try and find the article and post a link.
Dino


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## GeoffD (Dec 21, 1999)

In fact ford still has issues with auto trannies, they just recently had to halt production of all gas powered trucks due to a diode failure in the trannies. Diesel powered trucks were not affected because the faulure would only occur after full throttle above 4700 rpm let completely off the throttle and then back to full throttle. I am not picking on fords but read the article from dearborn news or something to the like. I will try and find the article and post a link. 
Dino 

That problem occured back in november or december. I am pretty sure it's fixed now.

Geoff


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## mike48114 (Aug 13, 2000)

sorry about everyones situation but i know what the proublem is... In a Ford truck the only way that light can blink is if the trans is over heating or if the speedomoter fuse is blown, but you would know that one becouse your speedomoter wont work at all.... i have this happen alot and you just have to find what made the trans over heat... the reason these other guys had pricy repairs is couse they let it happen to long and it fried the trans or the repair shop milked them...


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## Shack (Dec 5, 2000)

I have a tranny cooler.


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## John DiMartino (Jan 22, 2000)

I know from the TDR,that Ford tranny coolers are sized way to small-bur why is it doing it all the sudden?


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## 99SDPSD (Jan 20, 2001)

On the 99 and newer the overdrive light will blink if the speed sensor is bad.


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## Randy Scott (Nov 6, 2000)

You know something, you guys piss me off! (LOL) Just kidding! I have a 2000 F250 4x4 PSD with 20,000 miles on it. No problems or complaints, until this afternoon. The fricken' overdrive light started blinking, no BS. I never heard of this problem until a couple days ago from you guys here, and now mine is doing it. You guys jinxed me! Well anyways my buddy is a mechanic, has been for 15 years, and he said most likely it may be one of the sensors. Since my tranny hasn't been acting up or anything yet. I need to have him do a test on it since everything is computer and/or electronically controlled. I'll let you guys know how it turns out.


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## Randy Scott (Nov 6, 2000)

Finally got my truck fixed, waiting almost a week for parts and then trying to find time to give it up for a day. They replaced the PCM (power control module) EEC Processor assembly (whatever that is) and a new main control valve body. Seems to be fine now, time will tell if this is going to be a problem in the future or not.


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## Shack (Dec 5, 2000)

G0t the old Ford back today. The problem was a tach sensor. Cost a $154.38. The part only cost $50.27. What the tach sensor has to do with the tranny and a blinking overdrive light is beyound me, but I am sure glad it was not something else.


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## Shack (Dec 5, 2000)

@#%$#@^%# overdrive light came back on today. This time the tranny is shifting hard, and I cant get the button to go in. What a $^#@$^ bad time for this to happen.


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## powerreel (Sep 25, 2000)

I'll tell you I hate Ford trannys! You have to have a flusher to get all the fluid out, dropping the pan is only part of the system.Sucks!!!


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## Cleve (Dec 23, 2000)

> _Originally posted by powerreel _
> *I'll tell you I hate Ford trannys! You have to have a flusher to get all the fluid out, dropping the pan is only part of the system.Sucks!!! *


Not true. In fact, a flusher will NOT get all the fluid out. 
You have to remove the TC inspection cover and rotate the TC until the drain plug is on the bottom, remove the plug and let it drain. And, drop the pan along with blowing out the cooler lines. This will remove all the fluid.
A flusher will only remove some of the fluid and leave a lot of the old fluid mixed in with the new.
Cleve.


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## snso (Mar 5, 2008)

*Unbelievable...*

97 F350 - blinking overdrive light started last night - found this thread via Google search this morning; purchased a set of fuses ($16); replaced the one for my speedometer (which was blown) - and unbelievably - the light went off (am back in Odrive) and the speedometer is working...this is such a relief...had already called the Ford dealer to see when I could bring my pickup in...thanks mike48114 for your advice.



mike48114;24875 said:


> sorry about everyones situation but i know what the proublem is... In a Ford truck the only way that light can blink is if the trans is over heating or if the speedomoter fuse is blown, but you would know that one becouse your speedomoter wont work at all.... i have this happen alot and you just have to find what made the trans over heat... the reason these other guys had pricy repairs is couse they let it happen to long and it fried the trans or the repair shop milked them...


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## WOODY367 (Dec 19, 2002)

I had the same problen. They cleared the code twice and was told it needed to be rebuld.. After that I took it to a tranny shop I deal with. It was a internal problem. Ned\eded to rebuild the tranny.$950 later it runs good. As the overdrive light stayed on the tranny would start to shift harder. It was the tranny building up presure to compansate the problem. At the end it wouldn't always shift into OD.


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## zapster (Feb 21, 2006)

'99 7.3 F-350 Dump..
Mine has been doing the blinking lite thing every 4-5 Months for 4 years now..
When the lite is blinking the speedometer don't work either..
All I do is pull over..
Shut it off..
Count to 10..
Restart and continue..

Works (for me anyway) everytime and I beat the crap out of this thing..

...zap!


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## ron222 (Oct 20, 2010)

I benefited from reading everyone's post about the blinking overdrive light issue but I thought I better post what I learned about mine, since I did not see anything like it posted. Best of all my "find" saved me ALOT of money!!

I have a 2000 Excursion 7.3 with the 4L80E tranny. The O/D light would often come on but only when I was starting from a full stop. There would be some clunking. I would stop, turn the truck off and upon restarting everything would seem normal.

I happened to notice the idiot light for the alternator flash on briefly so I checked my voltage. The alternator was failing (about 11 volts). Replacing the alternator has FIXED my tranny problem also! By the way I followed up at a GOOD tranny shop and my suspicions were confirmed. The tranny keeps rolling 

My fix was obviously ALOT cheaper than a tranny! I know everyone's situation is different but this is something easy to check before big bucks are spent.


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## Too Stroked (Jan 1, 2010)

On a Ford truck, a blinking overdrive light is a signal that any one (or more) of a number of things are wrong. Anybody who tells you – over the internet – that “your problem is …” is blowing smoke up your skirt. The only way to truly know what it means on your truck is to take it to a professional and have them scan for codes.


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## 2COR517 (Oct 23, 2008)

I had a truck with a 4L80. Great transmission.


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## Mattsautobody (Dec 14, 2009)

Cleve;24884 said:


> Not true. In fact, a flusher will NOT get all the fluid out.
> You have to remove the TC inspection cover and rotate the TC until the drain plug is on the bottom, remove the plug and let it drain. And, drop the pan along with blowing out the cooler lines. This will remove all the fluid.
> A flusher will only remove some of the fluid and leave a lot of the old fluid mixed in with the new.
> Cleve.


if you have over a 100k and have never flushed or changed the fluid, the only thing flushing will do is stir up all the crap settled inside and send it through the trans which will trash it. just drain the torque converter, change the filter and fluid. use mercon V fluid, and btw when the OD light flashes, it means there is a trouble code for the transmission. and with it being an E4OD, it may need a solenoid pack due to the intermittant hard shifting.


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## Mattsautobody (Dec 14, 2009)

also.. the reason a ford t/c would screw up would be LACK OF MAINTENANCE!! I have two broncos 93/94 and they both ended up needing solenoid packs, the had a wiring issue as well. if you go to www.ford-trucks.net and get the trouble codes and the pins to jump on the EEC-IV connector, and count the flashes. it's free for you, as this only relates to trucks up to 1997. E4ODS are good trannies as long as you take care of them...


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## 2COR517 (Oct 23, 2008)

What's the best way to drain the torque converter?


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## PeteB4 (Aug 27, 2006)

My ABS light came on, occasionally speedometer won' work and when this happens OD light blinks. I think it's a bad speed sensor. What do you guys think? 2000 F350.


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## Drottlawn (Jan 14, 2005)

PeteB4;1094746 said:


> My ABS light came on, occasionally speedometer won' work and when this happens OD light blinks. I think it's a bad speed sensor. What do you guys think? 2000 F350.


U nailed it right on the head! My 350 did the same exact thing, replaced stupid sensor and every is great. My older truck that I dont have anymore did the same thing and it was also the speed sensor. Very common problem on them


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## PeteB4 (Aug 27, 2006)

Drottlawn;1096050 said:


> U nailed it right on the head! My 350 did the same exact thing, replaced stupid sensor and every is great. My older truck that I dont have anymore did the same thing and it was also the speed sensor. Very common problem on them


Thanks Drottlawn!


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