flashing O/D light on 95 explorer

[Rolla91]

About 20,000 miles ago my o/d started flashing a few times, when that would happen the transmission would down shift and up shift very hard, I reset the computer a few times and it was fine, shifted normal, everything worked fine, untill now. Today While driving in 16+ inches of snow my o/d light started flashing, it started the hard shifts so i reset the computer, this time the light instantly begins flashing when you start it. any ideas on what this could be? if i am accelerating fairly hard and let of the gas completely it also makes a clunk, is this related? its done the clunk problem for nearly 40,000 miles, just has started doing it often recently, and still only about once every 800 miles. thanks for reading this

 

[MrShorty]

As I understand it, a flashing o/d light on these means that the computer has detected faults in the transmission and is just dying to tell you what they are. So, the best place to start is to pull codes from the computer. Most '95's are still EEC-IV/OBD-1, so you should be able to pull codes with nothing more than a paper clip. See my notes on pulling EEC-IV codes in the EEC-IV forum.

 

[Rolla91]

I have one of those 40$ code readers from autozone, will this work?

 

[MrShorty]

Should work just fine.

 

[Rolla91]

Ok, well this morning I got my code reader and went outside and started the truck, no flashing light, no hard shifts, everyhting is fine. could the computer just glitch sometimes or what else could cause it to think there was a problem one minute and the next it is fine?

 

[MrShorty]

Or a loose connection or some other intermittent fault.
I'd still pull codes. The computer has a memory section and I would expect a fault that caused the light to light up should leave a code in that memory section to tell you what problem it was seeing.

 

[beenwrong2002]

About 20,000 miles ago my o/d started flashing a few times, when that would happen the transmission would down shift and up shift very hard, I reset the computer a few times and it was fine, shifted normal, everything worked fine, untill now. Today While driving in 16+ inches of snow my o/d light started flashing, it started the hard shifts so i reset the computer, this time the light instantly begins flashing when you start it. any ideas on what this could be? if i am accelerating fairly hard and let of the gas completely it also makes a clunk, is this related? its done the clunk problem for nearly 40,000 miles, just has started doing it often recently, and still only about once every 800 miles. thanks for reading this

on my 96' X my O/D light will start flashing after going high speeds for long long periods of time. When I go to slower speeds it upshifts and downshifts hard. After letting it sit for a while it stops doing all of it. I still dont know what the deal is...

 

[Charlie]

I have had problems similar to this. Resetting the computer worked great for me, and I have never had the problem again

 

[Rolla91]

I tried to pull the codes but the only one there was for the EGR valve. :thumbdwn:

 

[tktrain]

This could be as simple as a sensor going bad or it could mean something like a slipping lock-up torque converter or internal fluid leakage indicating that the transmission is worn badly. If it can be fixed with a simple reset, great! But you need to pull the codes.

When transmissions shift hard it is an internal compensation that the PCM goes into in an attempt to help keep the tranny alive. Depending on what the codes tell you, you may need to have the thing looked at by a technician with a breakout box. The breakout box takes a highly trained transmission technician to use correctly, but it will tell him exactly what the transmission is doing and what it needs.

 

[NHale623]

If it can be fixed with a simple reset, great!

This comment never ceases to amaze me. What exactly are you "fixing" by resetting the computer?

 

[1karkrazyguy]

Hi,

Take things step by step in figuring out what is wrong.

Try reading this posting first on figuring out what is wrong with your transmission.

http://www.explorerforum.com/forums/showthread.php?t=170162

Taking off the battery cable and "resetting"/erasing all the stored faults in your PCM computer DOES NOT fix the problem. The problem is still there and the fault codes will be stored again in the PCM as you drive. You may have a mechanical problem in the transmission, or a problem with a sensor/sensors on the engine or the transmission.

Have a FORD dealer or a certified transmission shop put their scan tool to get the OBD I DTC codes from your truck. Some scan tools do not give you all the trouble codes.

If you have a 4R55E trannie in your truck, pretty easy to figure out what is wrong with it once you have all the codes.

Good luck and hope this helped.

Nick