2004 F150 with no overdrive and code P0734

Northman1 · #1 10-06-2009, 06:18 PM

Hi all, this is my first post here. Here's the situation: I am unable to use overdrive on my f-150. It has the 5.4l motor and shows no check engine light.

A code reader shows P0734 - Gear 4 incorrect ratio.

I'm hoping that someone else has had this problem and can tell me what to expect for fixing it, hopefully it is something i can do at home.

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desparado · #2 10-06-2009, 11:50 PM

I had the same happen to my 01. You don't say whether the engine tries to shift into overdrive and then seems to be in neutral, or does it just stay in 3rd and never attempt to shift.
If if goes to overdrive and seems to be in neutral, that is the problem I had, and the fix is not too difficult: the 4rw70 which I have, has a weak overdrive servo retaining ring. This ring broke on the eylet end, and the tiny 1/8 inch piece migrated into the valve body and jammed the pressure regulator valve. I had other issues not related to a stock transmission valve body.
I did not have any codes, but my truck is older. (checked with Auto Xray with enhanced Ford program)
You probably have the 4r75w, so this may not be your problem. I am not a transmission expert, but this is my experience. Hopefully, the gurus will weigh in with their thoughts. Whatever you do, don't go out and buy a new tranny until you pull the pan and check things out. Most tranny shops will tell you your trans is toast and sell you a new one. My 4r70w has 120K miles, behind a tuned and supercharged 5.4, and it was spotless inside.
PS If you pull the pan, install a drain plug. It is cheap and will save you the worst mess you can imagine.
Good Luck!

Northman1 · #3 10-07-2009, 09:14 PM

Thanks for the reply.

The transmission _does_ try to get into 4th, then just revs as if it were in neutral.

Not sure how to check which transmission is installed, but i think someone told me (or i read somewhere) that all 2004's with the 5.4l have the 4r75e installed.

Are those two transmissions much different at all? the 4r75w and 4r75e?

desparado · #4 10-07-2009, 10:06 PM

I'll bump this up for you, since I don't know the answer to that question. I would assume they would be similar, but I know there are real experts out there who can give you a definitive answer. Hang in there and good luck!

Paralyzer · #5 10-07-2009, 10:55 PM

anytime you get an incorrect gear ratio DTC that indicates slipping(band,clutch, broken gearset ect) start by pulling your dipstick and check the color of the fluid and see how it smells. That should always be the first step in trans diag.

Northman1 · #6 10-07-2009, 11:15 PM

Sorry, neglected to tell you all that part.

As soon as i realized that o/d wasn't working proper - i did just that, the dipstick was full and didn't smell fried at all. Its colour was also still proper.

Rechecked the dipstick later on that night; as well as checked under the vehicle, and there was no fluid loss at all.

Thanks all for the step by step help =)

Paralyzer · #7 10-07-2009, 11:51 PM

possible broken OD band, do you have manual 2?

desparado · #8 10-08-2009, 12:24 AM

Paralyzer,
Good call. I forgot that diagnostic step, even though I used it 2 weeks ago!
My manual 2 worked fine, so I was very optimistic that the servo or ring was the issue. I was never so happy to see that broken ring!

Paralyzer · #9 10-08-2009, 12:35 AM

looking at the apply components for the 4r75 the od band is the most probable failure since he has the first 3 speeds. weather it be broken, slipping or servo not applying it. The only other time the OD band is applied is in manual 2 so if he has manual 2 I would suspect a valve body issue.

desparado · #10 10-08-2009, 12:56 AM

Yeah, that's why I always like to start at the leaf and move my way to the trunk and roots...it involves a lot less digging. Start looking at the end that does the controlling, if all is well, move to the component that is controlled.