O/D light was blinking, now it's not.

[David in NC]

After arriving in town yesterday after 2 hours on the highway, the O/D light started blinking on my son's '97 4.0 ohv 4wd xlt. It continued blinking the rest of the day, but it's not blinking today. He says the truck still seems to drive normally and the O/D button still controls the overdrive. We recently changed the filter and fluid using Castrol Mercon V. I think the light started flashing a year and a half ago, then quit. Any advice? Thanks.

 

[ChrisTM]

Mine started doing this also. Shortly after it would accasionally refuse to go into first gear unless you put it into park and turned the truck off, then back on. After that you would be good for a few weeks... I would say it was 6-8months after that I started getting the 2-3 shift flare that I am tackling this weekend.

 

[imp]

Probable sticking Solenoid which controls engage/disengage of Torque Converter Clutch. Taking a trouble code reading, when the damn light IS flashing, will confirm, or disprove this.

When the light IS flashing on and off, for the above reason, the clutch is most likely failing to engage, which can be detected by slightly higher engine speed at cruise, above about 50 mph. imp

 

[David in NC]

Thanks. A sticking solenoid sounds better then a failing transmission. If this is the case, is it worth just switching out the solenoid, or should I have the tranny rebuilt while the mechanic is in there? My son commutes about 300 miles every third or fourth weekend and he'd hate getting stranded.

 

[imp]

Thanks. A sticking solenoid sounds better then a failing transmission. If this is the case, is it worth just switching out the solenoid, or should I have the tranny rebuilt while the mechanic is in there? My son commutes about 300 miles every third or fourth weekend and he'd hate getting stranded.

5R55S 5-speed automatic has eight solenoids, one each for shifts 1-2, 2-3, 3-4, 4-5, three for hydraulic pressure control, and one to engage/release the Torque Converter (lock-up) Clutch.

If only one of them is indicated as faulty, they may NOT be individually replaced as in earlier transmissions, but are all 8 molded-in to a "module" which is easily removable from the Control Valve Body, and replaced. (parts new about $300).

Three externally transmission-case-mounted speed sensors feed shaft speed data to the PCM (computer) whenever the transmission is in operation. The shafts involved are the Turbine (or torque converter output, or, trans. input, if you prefer), Intermediate Shaft (planetary sun-gear speed), and Output Shaft (or, driveshaft). Comparing relative speeds among these shafts allows PCM to determine, based upon each gear range, and T.C. Clutch demand, whether anything is amiss and causing inappropriate shaft speeds to be present. The "OD OFF" light flashing on/off was chosen as a means to alert the driver of a fault existing, which is unrelated to emissions-control, and therefore does not warrant an immediate MIL (Check Engine) light to be locked-on permanently (until problem fixed, or code deleted from PCM). This is actually a marvelous self-diagnostic system which can "catch" and often prevent a catastrophic failure.

Shifting problems (slippage, missed shifts, etc) are often driver-detectable. T.C. clutch problems are less driver-obvious, and hydraulic pressure control faults may cause a myriad of problems. You really need to record the code(s) generated to make any further decision-making realistic. imp

 

[wow97]

i have one question i have a 1997 ford explorer xl 4.0 ohv v-6 with 5-speed automatic with 4x4auto 4x4 high 4x4 low if i dont warm up tranny it slip if i warm tranny 100%perfect no problem i change tranny filter oncei warm tranny she run perfect my have no money to fix tranny my wife said i so $2,000 fix like brand new from ford dealshiper told us long time warranty for lifetime if my and wife fix NOW

 

[imp]

i have one question i have a 1997 ford explorer xl 4.0 ohv v-6 with 5-speed automatic with 4x4auto 4x4 high 4x4 low if i dont warm up tranny it slip if i warm tranny 100%perfect no problem i change tranny filter oncei warm tranny she run perfect my have no money to fix tranny my wife said i so $2,000 fix like brand new from ford dealshiper told us long time warranty for lifetime if my and wife fix NOW

How long has it been doing this, and how badly does it slip? If it goes away pretty quick, no money to fix, keep driving it. It will let you know when it is "time".......imp

 

[wow97]

stop slipping i guess next day it went back to normal nomore problem after week later my wife and i warm up 1997 ford explorer in the winter fall season i wait to warm up once warm up
my 1997 ford explorer great 100% perfect

 

[khj]

After arriving in town yesterday after 2 hours on the highway, the O/D light started blinking on my son's '97 4.0 ohv 4wd xlt. It continued blinking the rest of the day, but it's not blinking today. He says the truck still seems to drive normally and the O/D button still controls the overdrive. We recently changed the filter and fluid using Castrol Mercon V. I think the light started flashing a year and a half ago, then quit. Any advice? Thanks.

My 97 ex was doing the same thing, OD light blinking then not blinking, off for a few days and the the blinking would start again and no noticeable driving issues. Had a code pulled at my local tranny shop($85.00)when the light was flashing and did some research on the net for that code and it was failure to engage lockup converter. Did some more research and found a tsb stating that there is a seal in the tranny oil pump that goes bad that is ususally the culprit. Tranny shop wanted to do a complete re-build ($2100.00). I flushed trans fluid, did a filter change with "high mileage" tranny fluid and added 2 quarts of Lucas trans. conditioner. May just be temporary but it's been a couple of months now and no light. Also one way to tell if the lock up is not working properly is to watch the tach when your on the highway and in OD. If it's working properly(no light flashing) when you gradually accelerate the RPMs will gradually increase.

 

[khj]

My 97 ex was doing the same thing, OD light blinking then not blinking, off for a few days and the the blinking would start again and no noticeable driving issues. Had a code pulled at my local tranny shop($85.00)when the light was flashing and did some research on the net for that code and it was failure to engage lockup converter. Did some more research and found a tsb stating that there is a seal in the tranny oil pump that goes bad that is ususally the culprit. Tranny shop wanted to do a complete re-build ($2100.00). I flushed trans fluid, did a filter change with "high mileage" tranny fluid and added 2 quarts of Lucas trans. conditioner. May just be temporary but it's been a couple of months now and no light. Also one way to tell if the lock up is not working properly is to watch the tach when your on the highway and in OD. If it's working properly(no light flashing) when you gradually accelerate the RPMs will gradually increase.

if it's not working properly(od light blinking) you will see the tach jump about 1000 rpm when you gradually accelerate

 

[imp]

if it's not working properly(od light blinking) you will see the tach jump about 1000 rpm when you gradually accelerate

You are right on about watching the tach! Trick is to be holding gas pedal steady, speed steady, and increase gas pedal very slightly-- the tach. should very slowly begin to go up, as car speed goes up SLOWLY. If tach. jumps up right away, clutch is not engaged. If you zap the gas pedal a bit too much, this unlocks the clutch (assuming it's working), and you lose track of whether the "test" proves out the locked clutch.

One other thing: When cruising with constant gas pedal, and you let off the gas, the clutch unlocks; this is the way Ford programmed the system to work. I don't entirely agree with it, but that's another issue altogether! imp

 

[khj]

You are right on about watching the tach! Trick is to be holding gas pedal steady, speed steady, and increase gas pedal very slightly-- the tach. should very slowly begin to go up, as car speed goes up SLOWLY. If tach. jumps up right away, clutch is not engaged. If you zap the gas pedal a bit too much, this unlocks the clutch (assuming it's working), and you lose track of whether the "test" proves out the locked clutch.

One other thing: When cruising with constant gas pedal, and you let off the gas, the clutch unlocks; this is the way Ford programmed the system to work. I don't entirely agree with it, but that's another issue altogether! imp

Agreed, you have to accelerate very slowly to see this and be in OD. I noticed it first cruising at abot 60 MPH and trying to maintain that speed going up a hill thus increasing load and the tach would jump 500-1000 RPMs' and no equivalent increase in speed compared to the jump in RPMs'.

 

[juggaloscorpio]

o/d flahing and not meaning to thread jack

i made a 3hr road trip from sherman,tx to pick up my lil girl and the baby momma on sun and the whole drive was good on the way down there until about 20 mins outside of west,tx when the rpm's started to jump up and down from 2000rpm's to 2500rpm's with steady pressure on the gas and a constant speed being held... it feels like im loosing 5th gear as it wont stay engaged and the rpm's are not steady like normally.... i did make it home on the 3hr trek back but i gotta get my tranny shop to run the code if one is present(currently have a cel for my bad egr valve)... this is my daily driver and other than the highway my ex drives just fine for city driving(under 50mph) with the exception of the rear differential whine.. i dont have the o/d light flashing anymore until about 65 or higher now but will update when i get the code
-yo majik ninja