1998 F150 flashing Overdrive Light

Update

I went under to look at the filler tube, its rusted in half about halfway to center.....the ear with the bolt is still connected to the block ok.

Looks like someone put tape or something around the break, some kind of vinyl sleeve maybe.

Thursday a shop will be putting the new one in for me and checking the fluid level. OD light has not flashed, I notice maybe some difference in shifting, taking longer from

I threw the OBD reader in there this morning got:

P1537/P1538 (Already known , IMRC solenoids)

P0136:

If you can Easily get to the O2 sensor pins then you could check the heater ohms. Or, if the sensor can be removed without destroying it then you can bench test the heater ohms and also sensor volts with a propane torch. At least that would confirm sensor condition before checking the really difficult to check wiring.

New filler tube is in via a service station.

Looks like it was a bit low on fluid, light has not flashed anymore so I will probably wait a while before I bring it in for more service.

Its likely needing a fluid / filter change soon as I have no idea when that was last done.

The fluid is still pink I think, so probably ok.

The trans fluid cooler lines are a bit corroded so I may have them replaced at that time as well to avoid problems.

Hard to find transmission shops these days like AAMCO or back in NY it was Dr. Nicks.

Are those cooling lines usually custom made at the good shops, or best to order online?

You will have a like new truck by the time you are done! Personally, I would get the ready made ones if available. Steel or stainless is not easy to fab and get all curves, fittings, and flares correct.

Yes, well it seems to be doing the job for me fine, just put 1200mi on it with a trip to New England and it was rock solid.

Aside from some frame rust where I spot a pinhole here and there and get it welded its just a matter of keeping up with the normal maintenance.

Dorman sells frame patch panels which I may try at some point.

Ford has a recall on the gas tank straps but they seem ok, they did say the piece they mount to is rusting out, as well as the spare tire cross member in back. They sell that as a new piece I guess to be welded in, but not sure bout the gas tank mount.

The 4.2L "isolator bolts" are a known issue and right of passage on these, mine are causing some rough idle at full stops in drive, if you switch to neutral seems ok.

The error codes for the IMRC's I was trying to address, so bought (2) new IMRC's just need to find a shop confident enough to do the job, and the isolator bolts can be done at the same time:

Sounds like the IMRC's are there to help with low end torque?

\ Is it a safe guess that when the OD light flashes, its just notifying the driver the computer threw new codes?

The ones it threw in my case were not related to the transmission but the O2 sensors....

Not exactly. It's notifying you that the transmission control computer is unhappy, not the ECU. Could be anything from a bad sensor to a failing transmission-- you don't know until you use a tool that can look at the TCM codes and the transmission data.

Well, you might want to look at that as well, then, but that's not why the light is flashing.

--scott

Last night after a huge amount of rain the flashing came back briefly,

Not had a chance yet to plug in the code reader yet.......

Light is flashing more often, OBD reader reads same codes..... seems to happen when u make a right turn or hit some rough road that make the truck vibrate so am thinking its that passenger side cable harness as the last time I pushed it, the flashing went away for a long while.

Agreed.

Deep dived into more utube stuff, one vid says theres an electrical connector to the transmission housing which if comes off, causes the light to flash, but its for a Ford Bronco and it says it causes the engine to not start as if the solenoid is bad.

Might be a different transmission than my 4R70W auto tho.....

Which tells you nothing since you won't be able to read the transmission control errors with a cheap code reader. You need to rent or borrow the proper tool so you can see the errors that are logged.

Could be. Who knows?

--scott

The flashing light is telling you that the TCM has logged an error. Many different errors are possible.

--scott

AI says my Truck dont have a seperate TCM, rather its integrated in the PCM.

Yesterday while doing some local driving, it turned OD off, so the OD light on the shifter stays lit illuminating "Off" condiiton.

It never flashed all that time, so I left it off as Im not doing much highway drive lately.

Apparently u can reset it by disconnecting the battery or a "relearn" mode where u shift thru all the poisitions on the shifter at idle.

Will try that later to see if it clears.

One video I saw said their F150 has the TCM inside , accessable by dropping the pan.

This vid was also interesting

Well its been a few days after I tried the "relearn" mode to try and clear the trans-codes from the system and perhaps they were false positives for now.

Basicly you shift from Park to 1 slowly , with foot on brake pausing 5 seconds down and up to reset.

I have a OBD2USB cable arriving soon so I can run Forscan utility on a laptop etc in case these cods or others come back. My basic reader only goes so far I guess.....