I have an 01 f250 with a 4r100. Trans has not been slipping at all and yesterday it started a rough shift between 1st and 2nd. (3-4K Rpms) At the same time 4th gear stopped engaging. Shifts out of 3rd but does not go into 4th. I can hit my od button and it will shift back into 3rd and start pulling. Still no slipping just doesn't want to change 1-2 or engage 4th. I have done a full trans fluid change including new filter and tc. Old fluid looked fine with no metal flakes or garbage in it. So all new fluid still same problem. I was thinking of changing my shift solenoid. Any thoughts would be helpful?

 

Which shift solenoid? There are two.

With the OD OFF light on does it have engine braking at 40 MPH? Does it have engine braking at 30MPH with the shifter in 2?

Is the OD OFF light flashing?

 

Light is blinking . 0781 is code that it throws. Trouble shifting from 1st to 2nd. Engine break in 1st thru 3rd. It's like 4th never tries to engage.

 

Mine has the solenoid bank. Has 3 or 4 solenoids built into 1 with connecter that connect to pcm.

 

That code just means the 1-2 shift isn't right, or didn't happen.

Is this a diesel? Is it the original transmission? If yes to both, I have bad news. If it is, the problem is a failed mechanical diode one way clutch. The only fix is to rebuild the trans and replace the mechanical diode with a sprag type one way clutch.

 

I have the gas 5.4 engine. From what I have read it's the same one used in some of the 02-03 diesel and excursion.
1c3p-bc is the tag in it.

 

Both the gas and diesel trucks used the 4R100 transmission. Are they all the same? Not even close.

The problem mechanical diode was installed in all 4R100s at the start of the 2001 model year. A problem was found after a few 1000 of them were built, but not shipped to dealers. A decision was made to replace all of the transmissions in the gas models, since at that time it was thought that the problem only occurred above 4000 RPM, and the diesel couldn't run that fast.

All gas trucks were supposed to get a new trans before the truck left the factory. I have heard stories that a few slipped through the cracks and didn't get a new trans.

When was your truck built? The data tag in the driver's door jamb lists a month and year of manufacture.

 

Mark, could you share the differences with me please? I would like to know what I have ahead of me. .Ive built a couple of the diesel 4r100's and Ill be doing a gas burner here pretty soon. Im just wondering what the differences are. Thank you!


OP, sorry for the thread jack.

 

It was manufactured 10/00. That exact trans tag shows up on some of the diesel trucks.

 

A diesel 4R100 will not bolt to a 5.4L engine.

By 10/00 there should not be a mechanical diode. I'd only expect to see those (if any really exist in a gas truck) in a 07/00 build.

It could be a failing sprag one way. The sprag one way is a lot more robust, but anything built by man can fail.

 

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