Flashing O/D light

DRW1000 · 10-24-2005, 09:19 AM

Well I suppose it is my turn with the tranny.

While driving to work this morning my O/D light started flashing. I know this has happened to many. It was a quick flash rate. The van seemed to change from 1st to 2nd and to 3rd okay. I don't think it was going into O/D which doesn't surprise me since the light was flashing.

I know this is a common problem and since I am at work I can't really do too much searching but I wonder if anyong knows the first step in diagnosing the transmission. Is the transmission giving me a code with ther light? Are there codes to be read for the tranny?

Any other advice.

Thanks

lewisnc100 · 10-25-2005, 08:27 AM

Sorry to hear that, I'm guessing you need to take it in to read the transmission codes, can't read them with your OBDII reader. At least it doesn't sound like the common imploded sun gear, hopefully the codes will point to something less than a full transmission replacement.

wiswind · 10-25-2005, 09:07 AM

As Lewis has indicated....the flashing O/D light is like a "check engine" light for the transmission. This is the way that the transmission electronics indicate that there is a problem. Hopefully it will not be expensive....but the only way to know what the code is.....is to go have the codes read.

One not so expensive common failure is the Transmission Range Sensor (TRS).....which sits on top of the transmission. The cable from the shifter connects to it.....and it senses what position that the gear selector is in. There are a lot of contacts inside the TRS....and any one of them can become worn. They do not have to tear apart the transmission to replace it.

DRW1000 · 10-25-2005, 10:38 PM

Thanks for the responses. I did some searching in the forum last night and I don't think I found any real clues.

Sounds like the flashing O/D light is the CTL (Check Tranny Light). I suppose these codes are read from the same port but with a different reader.

The problem has not reappeared and it seems to be changing gears okay. I checked the fluid level too and it seems okay. A bit low but still in the correct range. I will top it up as it should be at the top of the line according to some other TSB.

wiswind · 10-26-2005, 12:13 AM

Mine did that once in a while during damp weather......before the car was really warmed up.....later, I ended up having the TRS changed......having the codes read did not give me anything to go on....."random fault" was what they told me.
If this happens again.......you can have the codes read. If they cannot give you anything to go on.....you could try buying a new TRS and changing it. If your transmission starts "hunting" as in shifting up and down.......you will want to get that looked into right away.

DRW1000 · 10-26-2005, 10:09 AM

Thanks Wiswind. It has been damp here the last few days. How much is involved in replacing it? (It's getting cold here..lol)

garync1 · 10-26-2005, 10:21 AM

Quote:

Originally Posted by DRW1000

Thanks Wiswind. It has been damp here the last few days. How much is involved in replacing it? (It's getting cold here..lol)

Not sure of your year but it should be up by the bell houseing with a plug running to it.I think there is 2 or 3 bolts with linkage running to it. hope this helps..

lewisnc100 · 10-26-2005, 10:53 AM

Looks like there is an alignment tool that you'll need, 307-351 (T97L-70010-A).

wiswind · 10-26-2005, 05:23 PM

I show the TRS on my '96, in the picture "Under the air filter" Looks pretty straight forward. I have not replaced mine (dealer did it), but if you do a search on here....you will find posts by people who have....and claim that it is very easy.

DRW1000 · 02-02-2006, 09:53 AM

Well I haven't had the tranny codes read yet but I am just rying to understand the behavior so that when I do I can be armed with a bit more knowledge. The light does flash on occasion but it does exhibit the following:

- It changes through all gears including O/D even when flashing
- It only starts flashing after I have managed to get to about 140 KM/Hr (I know I should not drive that fast)

If I stay to the safe speeds (120 and below - 70 MPH) It does not flash. I assume that the problem will get progressivley worse until I correct the fault. What I am trying to figure out is what happens at higher speeds and thus higher RPMs. It does not get to the "trigger" RPM until 4th gear. I imaging there is some internal pressue that occurs that causes the problem. I also assume that if I forced it to stay in a lower gear the problem would appear once the 3000-4000 RPM was reached.

I know I need to take it in but I just want to learn a bit more. If there are any opinions I would love to hear them.

thanks.

floridatgp · 02-03-2006, 10:42 PM

did you see my post from last weekend about disconnecting battery? my OD light is still no flashing, and the harsh shift from neutral to drive is still gone.
my symptoms were different light would flash first tranny was shifted into drive. I also added a can of snake oil from autozone, seafoam brand tranny treatment, it didn't help me, the brand does have some respect as far as there other product that cleans fuel system. it was one of the few tranny fluids that didn't claim to stop leaks, but free sticky valve bodies.

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