2003 F150 Transmission issues.

N80 · Oct 5, 2015

My old truck is starting to show its age. It has 124k miles on it. 5.4 V8, 4x4 Supercrew. For about a year it has some symptoms which I think are due to the transmission but they are intermittent and hard to pin down. It is almost a surging, shuddering sensation but it does not change gears. No change in engine RPMs. It almost feels like it is losing drive from the engine, almost as if you depressed a clutch pedal for a microsecond and then engaged it just as quickly. (Of course this is an automatic trans). The typical scenario is this: usually going about 40-55 mph with neutral or light throttle input. Almost always in overdrive but it will do it to a much lesser extent with OD off. It never happens under acceleration or braking. It never happens with a loaded trailer. No evidence of overheating. It seemed to get a little better following a recent change of transmission fluid but I'm not sure if they changed the filter or not. There have been no check-engine lights so I don't think it is the engine.

I'm pretty sure this is something I can't fix. The reason I'm posting is that I know nothing about automatic transmissions. I don't even know how to guess what is wrong or even how to describe it to a mechanic. It does not happen regularly enough to expect it to happen if they test drive it. But, when it does happen it is noticeable, even to passengers and now I'm too nervous to use it to trailer my car to the track or take any long trips in it.

Any thoughts or similar experiences would be much appreciated. Really hoping a transmission filter change might help.

George2615 · Oct 5, 2015

I'm no transmission guy myself but it sounds like the trans is not getting proper fluid flow. At 124K the fluid and filter should have been changed at least twice. At least that's when I change mine (50K). If you can change oil and filter on you motor its fairly easy to replace the transmission filter and fluid. Most auto parts stores have the filters in stock.
Not sure where you had fluid changed but there are some places that never drop the trans pan to even check the filter, they just suck out what they can and replace with new fluid. I'd change the filter and fluid to try and fix first. If that doesn't help then a trip to the transmission shop may be in order.

KubotainNH · Oct 5, 2015

This sounds like the issue my van has had in the past, it had to do with clogged EGR passages. It only happened in top gear at low engine speeds (45mph-ish) when lightly touching the gas. It is not a Ford but sounds to similar not to mention. A search google of f150 surging brings up a bunch of hits. Is the service engine soon light on?

interesting video: https://www.youtube.com/watch?v=HrMsh5ciVdY

N80 · Oct 5, 2015

I'm pretty sure filter and fluid changed around 50k. Certain that fluid changed around 110k but not sure about filter. All done at dealership. I'll check with them to see if filter changed at 110k.

3930dave · Oct 5, 2015

Consider speed sensors (and related wiring, connectors), if you haven't yet.

Transmission itself may have them, and many Ford trucks use a speed sensor in the rear diff. If the rear diff hasn't been serviced, sometimes all it takes is changing the oil and cleaning the sensor to cure what seems like a trani issue.

Rgds, D.

murphy1244 · Oct 5, 2015

On my Merc it was the variable cam sensors that needed replaced.

KubotainNH · Oct 5, 2015

3930dave said:
Consider speed sensors (and related wiring, connectors), if you haven't yet.

Transmission itself may have them, and many Ford trucks use a speed sensor in the rear diff. If the rear diff hasn't been serviced, sometimes all it takes is changing the oil and cleaning the sensor to cure what seems like a trani issue.

Rgds, D.

This makes me think of an issue Fords often have, the wire to the rear diff sensor sometimes gets intermittent. You may start to see it as a fluctuation in your speedometer needle. That will really confuse a tranny. The only thing that gets me is you say it only shows at certain speed/rpm/accelerator pressure. This is why I pointed to the EGR earlier. If you have a tach watch it closely when it happens.

tman1020 · Oct 5, 2015

Had a similar problem turned out to be a bad coil pack believe it or not. Before you do anything take it to an auto parts store have them pull codes. A slight miss in overdrive will feel like a transmission issue at times.

fordmantpw · Oct 6, 2015

I had a similar issue and like tman1020, it was a bad coil pack. Fixed that and the problem went away. About 1k later, the tranny went out though...

N80 · Oct 6, 2015

I would think that cam sensors, EGR valve, speed sensors and coil packs would all throw a CEL code. Not sure about the speed sensor on the diff but I think it would probably throw a code too.

One thought that has not occurred to me (big dummy) is to check the transmission fluid level.:ashamed: I will do that today. However, there have been no leaks that I can see so that probably isn't it either.

fordmantpw · Oct 6, 2015

Mine never threw a code for the coil packs. The coil pack can report back correctly but not work properly. The only way to know for sure is to test each one individually.

N80 · Oct 6, 2015

That is weird. Most vehicles are exremely sensitive to misfires and coil pack issues and throw a code. In my experience with other (Japanese vehicles) the CEL will come on for coil issues even when you cannot feel or sense that there is any issue at all. Anyway, I will keep that in mind.

KubotainNH · Oct 6, 2015

N80 said:
I would think that cam sensors, EGR valve, speed sensors and coil packs would all throw a CEL code. Not sure about the speed sensor on the diff but I think it would probably throw a code too.

Not always, it depends on how bad it is. Sounds to me like you are in the early stages of something failing.

Scooby074 · Oct 6, 2015

Check the rear pinion bearing & driveshaft U joints.

Mine is similar vintage and has a rear diff thats on its way out. Similar feelings of vibration. Speed dependent, around 85-110 kph. A known issue on these trucks.

3930dave · Oct 7, 2015

Have the spark plugs been changed, esp. recently ?

A guy I know changed them on his 5.4 not long ago. A little later the trani seemed to be acting up. Turned out he hadn't torqued the last plug down - it was still threaded in, but definitely not seated/sealed. That problem some of the time threw a coil code for him, but it definitely felt like a trani problem.

Rgds, D.

deerefan · Oct 7, 2015

My 1997 F150 did this, mainly in o.d. around 50-55 mph. A trans flush with filter change solved it.

caver · Oct 8, 2015

I had a similar problem (05 F150 5.4 w/125K) when lugging the engine in overdrive. Sort of felt like the transmission was shifting. My mechanic said Ford recommends replacing the plugs at 100K and he had seen this problem before. He did that and problem went away for awhile. It came back a couple months later and like the others mentioned, it was a bad coil pack. I can think of only two times it was bad enough for the check engine light to come on.

On edit: Originally I talked to a respected transmission shop in SE Missouri and he was the first to say it was a plug problem. He advised against opening the transmission up or changing fluid.

N80 · Oct 8, 2015

This just can't be a coil pack. A misfire sufficient to cause the truck to shudder would just about have to throw a code unless the ECU is really primitive (and it does not seem to be since it has thrown plenty of other codes for various tiny issues).

Anyway, I've been driving all week with OD off and no issues. Switch it on and it starts up again. Almost has to be the transmission. Engine and diff issues should not be dependent on OD. I checked trans fluid and there is plenty (well above the 'do not add' line....maybe too much?). Fluid looks new. Also, this does not happen when lugging overdrive. It shifts just fine. This only occurs in neutral or light throttle situations at 45-55. Never starting off, never climbing a hill, never while accelerating.

I think I'm going to have a flush/fill/filter change and see if it helps.

fordmantpw · Oct 8, 2015

N80 said:
This only occurs in neutral or light throttle situations at 45-55. Never starting off, never climbing a hill, never while accelerating.

I think I'm going to have a flush/fill/filter change and see if it helps.

Occurring in neutral leads me to believe that it is not a tranny issue. Or do you mean neutral throttle?

That is exactly when my coil pack would act up. I would notice it mostly when coasting to stop lights or lightly cruising at 25-30 down the entrance road to work. Acceleration would rarely cause an issue. Mine never through a code.

Another thought, have you changed your fuel filter? That is a quick and easy place to start if you haven't.

tman1020 · Oct 8, 2015

Sounds exactly like our coil pack issue. However if it's time anyway a transmission flush does not sound like a bad idea. We did not throw a code right away but it did eventually.