O/D Light Is Blinking but no error codes

[LMHmedchem]

Hello,

Today my O/D light started blinking. I took it home and attached my computer, but there are no codes stored. The O/D light was off when I started up again, so I drove around a bit. The truck seems to start fine from stationary and gets up to speed quickly. It does seem to struggle a bit and rev higher then usual to get into the next gear. I don't know if this is going from 1 to 2, or 2 to 3, etc. After a few times going through this, the O/D light started blinking again. Even though the computer was hooked up, there were still no error codes. I pressed refresh several times but still go nothing.

Not sure what to do without additional information. As far as I know, nothing has ever been done to this transmission and it has a bit less than 150,000 on it.

Thanks,

LMHmedchem

 

[JK080]

Some scan tools can't read transmission codes, the code should be stored in the memory even when the light is not flashing. You may have to swing it by a shop or try Autozone to get the codes. Sounds like you might be dealing with converter codes if you dont notice any drivability issues

 

[LMHmedchem]

Some scan tools can't read transmission codes, the code should be stored in the memory even when the light is not flashing. You may have to swing it by a shop or try Autozone to get the codes. Sounds like you might be dealing with converter codes if you dont notice any drivability issues

Thanks allot for the advice. I have had a bad torque converter ever since I bought this. It has always sounded like a box of marbles. I haven't had it repaired because what I read suggests that the noise alone wasn't an issue.

The only drivability issues are those I mentioned in getting to the next gear after starting from a stop. It isn't bad, but I do have to coax it a bit. If I keep it below 2000 rpm and work the accelerator a few times, it will bump up into the higher gear. If I just leave my foot down, the rpms will shoot over 3000. If I am careful, the O/D light won't start blinking. If I rev it too high pulling out from a stop, the light will come on. It seems just fine once I get up to 25-30 mph.

This is the scan tool I have,
ScanTool 425801 OBDLink SX USB: Professional OBD-II Scan Tool for Windows

I presume this is one that doesn't show the transmission codes since I am not seeing anything.

LMHmedchem

 

[plasticseng]

Try downloading Forscan for windows. It's free and will probably work with that cable. It will give you the transmission codes, as well as a whole lot of Ford specific codes that any of your generic software won't give you.

 

[LMHmedchem]

Try downloading Forscan for windows. It's free and will probably work with that cable. It will give you the transmission codes, as well as a whole lot of Ford specific codes that any of your generic software won't give you.

I have Forscan but I didn't use it when I checked the codes. I seem to remember trying it and not getting any output. Do I have to do something other than download and install Forscan?

I just tried Forscan again and it worked fine. I have three error codes stored, but none active.

DTC in IC C1284
DTC in PCM P0732
DTC in RCM B2292

The PCM code P0732 is for Gear 2 Incorrect Ratio, which is more or less what I am experiencing where the engine revs too high in second. I guess this could be the solenoid. I have also had some possible issues with my temp sensor reading too low and a faulty engine coolant temperature sensor is listed as one of the possible causes of this. I doubt that the trans fluid has ever been changed on this truck, so dirty fluid is another possible cause.

Should I replace the temp sensor first and see if that fixes the issue or should I be looking to take it somewhere and have the fluid and filter changed?

LMHmedchem

 

[plasticseng]

Sounds like the worn servo bore problem. It is very common on these transmissions.

Does it kick down out of OD under a light load? That is another common symptom.

 

[plasticseng]

Here is a list of other symptoms for the bad servo bores:

1. Transmission will not hold in OD/5th gear. It gradually gets worse. Eventually the transmission will not shift back into OD unless you were going down an incline. It will shift out of OD after any sign of load especially after the transmission warms up.
2. Transmission will shift fine when it is cold but then will exhibit shifting issues after it warms up.
3. Transmission will not shift out of 1st gear into 2nd. The engine will red-line and not shift unless you let up on the accelerator. It will shift from 1st to 2nd if you accelerated very slowly.
4. A combination of one and or two would produce a flashing OD light and eventually throw a service engine soon light.
5. Codes returned for the described situation P0775 Pressure Control Solenoid B Circuit Malfunction. Others such as P0732 incorrect gear ratio 2nd gear, P0733 incorrect gear ratio 3rd gear, P0735 incorrect gear ratio 5th gear, are also common.

 

[LMHmedchem]

I think that #3 is the only one that applies to some extent. The engine revs to ~3000 when it is going into second gear. It gets no where near red-line. I usually let off the gas when I sense the engine rev more that I think it should. If I keep the RPMs under 2000 when going to second gear, the OD light won't start flashing. I have to work the pedal a bit, but it will go into second. I am getting the P0732 code.

If anything, it seems to work better after it has warmed up. It's annoying to drive until I get up around 30 or so, then it's more or less normal. I am at 144,000 miles and I have never had the trans serviced. I have been reluctant to have it opened up since It has not before given me trouble.

I think I should try replacing the coolant temp sensor since I have some other evidence that it may not be working. I don't have that much confidence that this is the cause of the trans issue but I think it makes sense to replace the $25 part first and see if it helps. I probably need it anyway.

How much of a problem do you think it is to drive in this condition?

LMHmedchem

 

[Tylers02]

Sounds like worn overdrive servo bore if it's affecting 2nd gear. You can try to adjust the overdrive band and see if that helps. If it does you will want to look into servo bore o ring repair or a rebuilt with updated/sleeved servo bores. At your mileage i would consider the ladder as you said you have torque converter issues and I'm sure your solenoid block is long overdue for replacement. Personally I wouldn't change the fluid if it's never been serviced unless you plan on doing the servo bore o ring repair. You can also drive it till it dies and then throw in a reman but that's up to you. If you were at 70,000 and didn't have a torque converter that sounds like marbles I wouldn't suggest this but clearly that is not the case