I have a 1996 F-150 2WD 6 Cylinder 300 C.I. 4.9 Liter with an E40D Automatic transmission. Lately the problem has been happening more and more frequent. What it is doing is the word "Overdrive" on the shift lever starts to flash while driviing the truck, and then the trans starts to shift real hard (it actually jerks when shifting). Shutting the truck off and then restarting it will clear the problem. Does anyone have any ideas of what it might be? What to check? How to check it?
Thanks,
Tom Vance
thomasevance@gmail.com or simply respond to this post.

 

Could be a number of things and it would cost a small fortune to replace them all. The flashing light means that there are error codes stored. Get the codes read. A couple of obvious things are speed sensor and throttle position sensor. Does your speedo read OK? Does your engine stumble just off idle or at any other time? It sounds like your trans is going into limp mode so you want to get this fixes as soon as you can.
Hopefully some of the transmission experts will chime in soon. Good luck.

 

The truck runs perfectly smooth, without any hesitation even when the problem shows up. The only thing that it does is make the trans shift hard.

 

Also, the speedo is correct.

 

the wire to the switch may have broken off.

take the switch apart, carefully, and see.

 

Where should I check? in the shift lever or on/in the tranny?

 

the switch is in the shift lever.

 

I spoke on the phone yesterday with a mechanic at a local tranny place and he told me that the reason that the word "Overdrive" on my shifter was flashing was because an error condition was detected. He also added that there are sensors on the input of the trans and the output and that there was a difference between them (slippage) and that is why the tranny boosted the pressure which results in hard shifting. My big question to those of you out there that might be able to shed some light on this latest information, is where exactly are these Speed sensors? He mentioned the tailshaft housing and the rear end have Speed sensors, but which would be the culpret if it is actually a bad sensor giving me the problem. The trans shop wants $40.00 to run their OBD2 scan on the problem with the possiblity of it aking several hours of time (and additional cost) to finish diagnosing the problem. I'm not made of money and can't afford to be shelling out the money, let alone take time off from work to get it looked at. Any ideas guys? Plus, he mentioned that there are switch-on without running scans and switch on-engine running scans. Do they have a special OBD2 Code scanner, or is it the same that most auto parts stores have to read your codes for free?
Thanks,
Tom

 

Some parts stores will read your codes for free, or you can do it yourself. Do a search in the forum to find out how...

 

It sounds like an overheating problem to me. A faulty VSS would usually cause the speedo to bounce with the other symptoms you're seeing, it wouldn't hurt to check/clean it though. You could run a scan on it, but I'd also change drain the fluid from the pan and converter and cooler (if so equiped). Check/clean the magnet at the bottom of pan; some silt is normal, but larger particles would not be. The torque converter is the weak link in an E4OD and it could take out the rest of the transmission over time.

 

Matt,
The trans fluid was recently replaced as well as the filter. There was a very small amount of material caught by the magnet in the bottom of the pan, but no more than normal. The fluid was dark but not burnt.

The speedo doesn't bounce at all and even when it is acting up (which it did this evening on the way home from work) everything seemed normal. The Overdrive "Off" light started flashing, so I thought "oh what the heck" I was only going 45 MPH so I pushed the Overdrive button on the shift lever to see what it would do. The trans shifted out of Overdrive (hard) and then went back into the overdrive mode once I pushed the button again and again shifted hard. I came to a red light and put the trans in park, shut off the engine, then restarted the truck. The problem was once again gone for the rest of the trip home (6-8 miles). What is a VSS? Where is it located?
Thanks,
Tom

 

Several things can and will make a E4OD act like that, the stored trouble codes, CM and the KOEO test, is your best bet to start to diagnose the problem/s, doing anything without knowing what they are first is a waste of time.

You must correct any KOEO trouble codes, if any, before ever leaving the driveway with it.

 

Not to hijack the thread, but......... I have a '94 F150 with a 5.8 and an E4OD in it. It has 215,000 miles on it and I recently changed the fluid. It looked good, but I had just bought it and the guy said he had changed it but didnt remember when it was? Anyway I changed it ALL. I blew out the trans lines and cooler and drained the torque convertor. I had the starter off and with ALOT of trouble I pumped 3qts of fluid into the convertor with the convertor indexed to where the starter was bolted on.

I said all that to ask this. The thing seems to "slip" a little when it's cold, but does better when it warms up. I have to replace the rear main soon, and was wondering if it would be a waste of money to replace the convertor while I have all this apart? Or just wait and have it rebuilt later? I'd love to make it hold 1st gear longer and shift harder, but as far as I can tell it cant be done without spending a small fortune, and with high miles I think it might be risky??


What do you think?

 

Dan,
I normally love abbreviations, but work with me a little here... What does the CM stand for and what is the KOEO test? You mentioned getting this done, but I don't want to look too much like a puts when I go ask someone to run these tests.
Thanks,
Tom

 

You can do them yourself,

CM is "continuous memory". Basically error or trouble codes stored in memory while the truck was in use, problem encountered stored a code. The main reason you should never disconnect the battery, all code would be gone. The computer would have to relearn any problem before throwing the same code again, could happen right away, could take a few drive cycles.

KOEO is "key on, engine off" Basically this has the computer test all sensors for a problem. Be it a faulty sensor, or a bad connection with one it will let you know. If any sensor/system fails this test it will not work when driven. It can be and is a very handy tool for trouble shooting.

Your flashing light/limp mode condition is telling you there is a problem, the computer will tell you what it knows. But you have to take it from there.

Here's a link, Ford Fuel Injection How To Run a Self-Test

Google the tests and you'll find more.

You can do it with a paper clip or the best way is to buy a code reader, a Innova 3145 is a very handy tool and can be bought very cheap. Comes with a easy to follow instructions for all self tests.

Oh and it would also be best if you stop driving the truck until you correct the problem. You can tear up a expensive/heavy duty tranny because of something as simple as a bad connection or connections. Perhaps a PSOM (programmable speedodometer odometer module?) A VSS (Vehicle speed sensor) falure and you don't want to do that.
One thing I've learned from working one these trucks and the E40D, it is very likely just a bad connection causing your problem, not to say it can't be something more serious but.....