Bought a 1993 F-350 with 7.3 diesel engine a couple months ago. It was in great condition with only 140K for $4000, so it seemed like a great deal. But the day I picked up, the dealer had it detailed, after which he claims it started hard shifting into first and gear hunting. Seemed, like it might be a moisture issue and I thought it would dry itself out after sometime. But it has not.

Here are the symptoms: If I try to take off slowly it won't shift into second until I hit high RPMs and then it slams into second. But if I push harder on the pedal when I take off, it will go right into second, but then it will gear hunt, shifting gears 3 to 6 times before it settles down. It only has problems on take off. Once it is up to speed (30 MPH) it works fine. Also, there is a little light (the word OFF) that starts flashing on the gear shifter next to the the word "Overdrive". It does not start flashing until after the hard shift or hunting thing starts.

I have never owned a diesel with an automatic trans before, so I took to the truck to a transmission shop to have it looked at. It is a shop that has been around for decades and has a really good rep. The owner called me and told me that he could not do anything with the truck, because as he said, "Ford never released the codes for this particular model". He said he drove it around and felt all the symptoms I described. He said the fluid looked good and he did not feel that the problem was mechanical. He said the little flashing "OFF" light indicated that the problem was sensor related, but without the ability to read the error codes, he had no way to know where to start.

So, I figured I would try to replace the sensors myself. Since the truck was new to me, I went down to get a repair manual. Guess what? There is no repair manual for my year model. A friend of mine knows a retired Ford mechanic with 30 years experience. He talked to him about the problem and asked if he had a shop manual for the truck. To the mechanic's utter surprise, he could not find a shop manual for my model of truck.

So here I am. I have a truck that is almost 20 years old and nobody, not even the experts, seem to know anything about it. I am desperate here. I don't know what do next. I am hoping that someone here on this forum might have the same truck, with the same symptoms and can tell me how to fix it.

Any help or advice is appreciated.

 

1. Search on here for "E4OD" issues. Thats your transmission

2. buy a Hanyes/Chiltons manual. every auto store should have one for sale

The E4OD is very picky. Mine wouldn't shift out of first gear and I dreaded a full rebuild, turns out it was the MLPS sensor. The "off" light is a torque convertor clutch lock-up issue. The blinking is supposed to be a morse code but i don't know how to read it.

Welcome to the Forum! We would love to see pics of your new truck.

 

Thanks for the reply. I ordered a new Throttle Positioning Sensor. Everybody seems to think the TPS is the first thing to try. Thanks for the tip on my trans model. I looked everywhere to find out what trans my truck had. Info on my model of F-350 is almost impossible to find.

I uploaded some pick of my truck.

 

Buy a subscription from Alldatadiy.com it will have codes and troubleshooting charts.

 

Well, the trans shop you had it with is talking nonsense. The computer is OBD1 and getting the codes should not be a problem.
Your speedo needs to be working properly and the tach needs to be working and as already stated the trans range sensor needs to be good and the FIPL sensor (TPS) needs to be good and the voltage at it properly set.

 

Is there a way to test all these sensors without buying them? I tested the speedo with my GPS and it is within a couple of miles at 70mph (I have never found a speedo that was perfect). I ordered a new TPS and it should be here in a few days, so I will let you know the results after I replace it. But it could get expensive replacing all these sensors if I there is no way to test them.

I wonder why the transmission shop I took it to told me what they did? They had my truck for two days and did not even charge me a diagnostic fee. They are good people and I have used them for years. It just don't make no sense.

 

http://www.troublecodes.net/Ford/ Here is a link on how to get any trouble codes. The test connector should be on the drivers side inner fender under the washer bottle. You would need to wire in a small test light or meter as shown and count the flashes when the key is turned to on. You also need to keep the gas pedal floored (engine off) during the test or you will get a false TPS code.
Is your tach working properly?

 

Yeah, what Lazy K said.
The flashing OD Off light does not indicate what code, just that the computer has detected a problem... It could be sensor related, or mechanical...
E4ODs are notorious for acting up due to sensors. The computer needs good data from the VSS, the Tach sensor, the MLPS, the FILP (TPS), a barometric pressure sensor, and probably more that I'm forgetting...
If you search in the IDI diesel forum, you'll find all kinds of info.

 

Thanks for all the advice. My tach is working fine. Just checked it. I don't know how accurate it is but it seems to be within normal margins. It makes me regret that I did not wait for a standard trans when I here about all these sensors that control this E40D auto. Well, guess I am stuck with it now. Might as well try to figure out how to fix it.

 

Everyone talks about how strong the zf5 manul trans is but they are not without problems. My reverse synchro's are shot and second gear grinds sometimes. Clutch pedal brackets/ bushings, firewalls cracking, dual mass flywheel failures... I've never had an e4od but they are supposedly a strong trans and once you figure out how to pull codes the electronics are a little less intimidating.

 

it does sound like a faulty TPS.plus even if it's not,it's not a bad idea to swap them every 50k miles anyway.
this will help you with swapping that:
https://www.ford-trucks.com/forums/1...ions-only.html
it will serve you well to buy a code reader.it's also a very good idea to pull all the sensor clips,to clean and grease them every 5 years too.

 

Thanks for the info, but I could not find any instruction on how to actually swap out the TPS. As I said in my OP, there are no books for this truck. Can I simply, unplug it, take out the screws, remove it and replace it? Or is it more complicated then that?

 

Okay. I disconnect both batteries and swapped out the TPS. I ordered my new TPS (TH35T) from Amazon.com automotive, but it is black and not grey. I read that the gray ones were better, is this true? The one I took off the truck is gray.

Anyway, I still have shifting problems. The hard shifting from 1st to 2nd, has gotten better, but the gear hunting got a lot worse. Now I am really confused. I hate sensors!

 

you need to follow these steps in this order when diagnosing the E40D:
1.pull all clips.clean and grease and plug back in.focus on the one on the pass side (solenoid pack plug.)
2.pull codes.
3.test sensors,wires,plugs,whatever the reader points you too.
4.replace as needed.

as for the new TPS.don;t worry about the color of the plastic today.
why didn't you post what you set the new one to. idle and WOT?

 

Does the speedo jump around? I had some of the issues you have on my motorhome.
It was a bad harness on the VSS on thr top of the rear-end.

Hope this helps