I recently purchased a 1990 f250 7.3 turbo, automatic tranny and the overdrive light on the dashboard has been flashing. Does anyon eknow why? I dont have an owners manual to find out. Have check fluid, seems to be full. When the light is on it shifts real hard. any suggestions?

 

When the light flashes a code is stored in memory. You can buy a code reader for about $25 that will tell you what code has been set. Then we can figure out what's wrong.

You can also get the codes read at Autozone. They'll read them free.

 

Worth a try. I'll check out autozone. Thanks

 

>When the light is
>on it shifts real hard. any suggestions?

Get the codes read before you spend any money, but here is the most likely cause.

The torque converter lockup clutch is a known weakness of these transmissions. When it slips the computer increases hydraulic pressure to compensate, hence the very hard shifts.

Jim

 

When the light flashes constantly the trans has gone into failsafe mode to try and protect it self, it makes the shift with less clutch pack splippage to create less heat. I drove a truck for month's in this mode it had some lose wire connections causeing it but a computer should tell you whats wrong. I wish the truck would always shift that hard though

 

If you want to firm up the shifts inexpensively, add a Sonnax valve and Tricumulator springs. The parts only cost about $40, and the shifts are nice and firm.

Quadzilla
'95 F-350XLT Crew Cab SRW 4X4 PSD, 35X12.50X16.5's, Limited slip 4.10's, Hypermax downpipe, gutted EBPV, "Catless" in Seattle, "Renegade" 4" exhaust system, CTFD sticker, Air bags, TYMAR intake, shimmed fpr, Diablo Delta chip, Fumoto valve, Autometer pyrometer, Sonnax valve, Tricumulator springs, Tru-Cool, HX mod, Magnefine tranny filter, 4R100 pan.
And a wish list that gets longer every day.
(Thank God for a wife that likes big trucks.)
For pictures, click here: http://community.webshots.com/user/quadzilla100

 

Well I went to autozone tonight but as usual when you want something to be wrong so it can be fixed it's not. The light was off and would not come on so they couldnot tell me anything other than go to a dealer and ask then if they have any info. The light does flash steadily not in any sequence like a code, just a steady flash. thanks all. I'll keep checking.

 

The light only flahses a steady flash. The light does not have to be flashing to retrieve the code. The code will be stored in memory for about a month after the last time the light flashed.

You need to find someone that knows what they are doing. Some of the Autozones have people that can read codes, and some don't.

 

>You need to find someone that knows what they are doing.
>Some of the Autozones have people that can read codes, and
>some don't.

In my experience, AutoZone only has a few people who even know what a car IS!

 

...57

I think you can kiss your tranny bye. The flasher is a warning that you have tranny problems and are operating in a "standbye" mode.

Sorry bout dat.

 

Not always. It can be a minor problem, or it could be something big. You can't tell without knowing what code was set.

 

I've spoken to Ford here in NH and they tell me it is an electronic speed sensor sometimes gets a little goofy. If you turn it off it resets, or atleast my '99 dually does. 73,000 miles and it has happened 4 times

John

 

John,
How do you turn it off? Ever since I posted here the damn light has been off. Hocus pocus or what. My tranny shifts fine and the light has not been on for about 5 days. whats up with that? obviously something is on the blink. Still searching for a computer person our autozone here would not do it. I guess Ill have to go to a dealer and pay out the u know what.

Ken

 

I have been watching this post because my 96 PSD does the same thing. Flash for a couple days and then be normal for a couple days. Good luck.

 

I had the same problem.Like the previous letter,you can sometimes reset the hard shifting/blinking overdrive light problem by turning off the engine.I also find that if you gently shift gears for a little while it tends to go away as well.I found this out because Ford told me I needed a new trans. HAH! That was four years ago and it has been running fine.