sarahyost

2004 Ford F150 5.4 RWD FX4
I have seen this problem around the web but no solutions. Hopefully you guys can help.

What happened:
While driving on the freeway in traffic the cars slowed down so I decreased my speed as well but when it picked back up I could no longer accelerate. The rpm's meter would move but the truck would not pick up speed (just coasted down). It sounds like something is grinding under hood (unsure where).

Tried
Putting it in 4 wheel drive (nothing)
low gears (1, 2) (nothing)
Reverse (went for a second then stopped)
Checked Transmission fluid (no shavings, pink in color and doesn't smell burnt)

Known problems
Major Oil leak (currently has oil)
All catalytic converters need replaced (expensive!)

I have heard it might be fuel filter, transfer case, or transmission. I am on a very tight on money and unsure what to do. Please HELP!

GrimaceTimus

Yeah ... that's probably a toasty transmission. I suppose it could be electronic, but you said "the RPM's meter would move but the truck would not pick up speed" ...

So, this is definitely transmission. I would be surprised if it was the transfer case ... you also said "2004 Ford F150 5.4 RWD FX4" ......if you can try to engage your 4 wheel drive, that "RWD" should really be "4WD" ... as "RWD" means just rear-wheel-drive.

Anywho...I could be wrong, but I am pretty sure that even with a transfer case issue / bad transfer case, the transmission can still drive the rear wheels. With your rear wheels not even receiving any power, I gotta believe its the transmission.

EDIT: I just noticed how discombobulated this comment was....sorry, I am very tired. I think you have a transmission issue. If the transmission is not "bad" it could be the electronics associated with it.

sarahyost

thank you for that... I meant its rwd until you engage the 4wd high or low... Another possibility I heard was rear axle? Or fuel safety shut off? I'm completely stumped..

so what electrical components are you talking about? And how would I go about finding out? Is that something I should take to a transmission shop. I can't drive it is why I would be looking for a way to test it myself...

GrimaceTimus

The PCM control the shifting of the transmission. There are electronic components on the transmission that could be contributing to the issue...but I doubt it. It sounds like a smoked transmission.

If it was the rear axles, I'd bet that the truck (rear tires) wouldn't even roll at all. I would contact 6-10 shops and get a quote for transmission replacement using a salvage tranny and what it would be with a rebuilt tranny. You may have to go to a specialty shop, but professional auto repair shops can usually remove / install new transmissions, they just don't usually rebuild them (in house).

sarahyost

Wouldnt there be signs of a bad transmission though in the fluid? Just curious

GrimaceTimus

Well...as I said in an earlier post, I don't know for sure if the rear-wheel-drive is dependent on the transfer case. It may very well be. So, I guess if your transmission fluid looks clean, it could be the transfer case.

One thing to keep in mind however ... clean transmission fluid doesn't automatically equal a functional automatic transmission. There could be a blockage in the lines or the valve body ... or something that isn't allowing the fluid to move (like electronic shift control).

I think no matter how you slice it, it is a complex problem that probably needs professional diagnosis. If it was me, I would probably try to figure it out on my own ... but, while not a professional mechanic, I have quite a bit of experience working on cars and trucks (and motorcycles and boats...family business). Even so, the most foreign thing for me are transmissions. I've worked on them ... but nothing as "fancy" as one of these 4R70's or 4R75's.

sarahyost

Well thank you for that information. now the truck is not wanting to start. It sounds like it wants to turn over but just doesn't grab. I called around but it seems like it is stumping people on the phone (including transmission shop).. Thank you! I might just have to take it to dealer =/

primalurges

A double on the tranny, unfortunately. At 115k on an 04 I'm beginning to experience the same issue only it is typically followed by a load bang when it eventually engages. There may not be any visible signs of trouble in the oil unless the problem has gotten so bad that your just days away from getting stranded. As far as electronics go, I believe throttle position is one of the sensor that tells the electronically controlled 4R75 to shift so that may be causing the problem as could the electronic solenoids in the transmission valve body. It can also be a bad torque converter or a failing clutch. Unfortunately when it comes to transmissions just taking them down to figure out what's wrong can get pricey and often when torque converters start to fail they start to screw up other parts of the tranny. If you have a very trusty transmission shop you should have them take a look. Te dealership will probably just charge you $100 to tell you that it needs replacement.

Mechanik

I hate to say it, but a shop diagnostic is probably the best use of your money. I agree with others that the transmission is most likely the problem. The initial problem, plus the failure to start, could be anything from a serious mechanical problem to a fairly minor electrical or control issue. If you can spend $200 on diagnostics to find a cheap fix, that's a good deal.

Good luck!

GrimaceTimus

Wow, this is odd that your problems have now extended to the engine. You did say that it was running / increasing RPMs when you gave it gas yesterday, yes?

If the engine won't start now, I am leaning towards ...

Bad torque converter - (this may not eliminate the possibility of a full transmission failure) ... The torque converter is connected to the flywheel/flexwheel of the engine. Even out of gear, the torque converter is always spinning if the engine is spinning (starting, idling, etc.) This could also mean that there are major issues with the input shaft on the transmission. So...again, this is all leading to / pointing to transmission again.

While I guesstimate at least an 80% chance of transmission failure, it is still within the realm of possibility that there is an issue with the electronic shift module on the transmission. If the transmission shift control has the truck in gear (say stuck in overdrive), the truck just ain't gonna move...it could contribute to the starting issues. I think the chance of this is low, and even if it is the problem, damage to the transmission may have occurred anyway.

Personally, I would seek out a really good/qualified transmission shop. Note that I do NOT include the most popular "honk-honk" transmission shop in that category. I also think it takes a special stealership to have qualified personnel that can deal with complex tranny problems. I don't know what your urgency / timeline is, but if possible, take your time and find someone that is very experienced with the 4r70/4r75 transmissions.