Hello Ford Truck enthusiasts. I am very happy to finally be a member of your site. I've read your threads on Ford Truck issues and have always found them useful. I have a new problem that I need help with. I have a '97 F250 HD with 5.8 and E40D 4x4. After I put the truck in drive and accelerate, the truck goes back & forth between 1000-2000 rpms continuously until 35 mph, then it shifts into high gear and will not downshift. After that it runs fine -- the overdrive goes on and off with the button. Fluid and filter were changed by a transmission shop. No codes on engine or transmission. Transmission shop says it is a "ground issue" -- possibly in the PCM. Have checked all grounds on frame and engine -- all are good. Please help. Thanks. Secret Squirrel 53

 

The frame does not need to be grounded unless you are pulling a trailer but the body sure needs to be. The body ground is the ground for just about every thing on the truck. The engine ground is just for the starter, charging and spark.

That said what does your speedometer do all the time this is happening?

The body ground, note the small wires to the left coming out of the body ground point, that is the computer ground wires for pins 40 & 60.:


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Thanks for your great info on my ground issues.I was never told about the two pin grounds until now.After six months of trying to fix problem have good help.Spedo works fine.Replaced speed sensor,tps, fluid and filter changed.Trany shop put truck on computer and it drove and shifted fine and hooked truck computer back up and original problem came back.Was told only it was a ground problem.Ill be checking and cleaning grounds shortly. Thanks

 

Newby needs help. Would like to know if a 1994 ECU would work in my 1997 truck? Both trucks are automatic .The 1994 has a 302 and the 1997 a351.Thanks

 

No....not going to work.

 

Have tried all info given and problem still continues.Truck takes off and stays pinned between one to two k rpms back and forth until 30 mph where trans goes to forth and stays.Will not down shift. OD works fine.WTF?.Please help

 

What do you mean by "No codes on engine or transmission.".
Are you getting 111 in all three code read outs (KOEO, CM & KOER)?
Or are you not able to get any codes at all including the 111?
If you can not get any codes then more than likely you have a bad computer.

 

What happens if you shift it manually? Anything different?

All new to me, I'm just learning -rebuilding the E4OD in my Lightning ATM - but thinking maybe a prob with the intermediate sprag might cause what you're describing.

 

Subford Your knowledge on fords is awesome.ALL codes were 111 according to the Acton scanner.I used the EEC IV plug under hood on driver side.I also found a connector under ashtray that I have read is a code reading plug.Confussing situation.Just got off work and saw your post from this morning.Mucho Thanks.

 

Thanks for responding.When I manuall shift all is fine.Whats involved with a sprag repair

 

If the plug under the ashtray looks like the photo below it is for the Trailer Brake Controller and NOT for reading codes.



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Pulling the trans out, tearing it down, and rebuilding it, replacing the sprag.

 

Please tell me what E40D tranys will work in my 97 F250 HD?Will half ton and SUV tranys work? Desperate to get my truck fixed.Al lhelp needed.

 

You'll need to find one from another truck that has a 5.8L and 4x4. That's going to be either an F-250 or F-350.

 

I don't think it's a transmission issue if it works fine in the manual ranges. I'm not sure what you mean by it goes between 1000-2000 RPM over and over. That's not particularly descriptive.