I've been trying figure out what is currently going on with my truck. I have a 2008 Ford F150 4.6L @ 120000 miles or so. Everything began one day with a subtle jerk at takeoff when in drive and the trans fault code (with a blinking O/D light). You could feel a jerk when you went from a stop to a go. And you would feel it worse if you put more throttle behind it.

I ended up replacing the transmission filter and fluid in the pan. This did not improve anything. So afterwards I talked to a neighbor mechanic and he suggested changing the TC Clutch solenoid and the Trans shift solenoid. I did both and noticed a significant improvement. Afterwards I took the vehicle for a test run on the interstate and then the truck had an issue holding a gear at 70 mph. If I bumped it to 75 it settled down. It would shift hard as i let it accelerate and after a certain point the RPM's would go up but the MPH would stay.

Right now the truck runs fine with small jerks on the down shift and a sticky shift going up. Still with the trans fault code. I haven't tried going back on the interstate (afraid to do any damage), but right now the truck is driveable.

Is this a transmission problem or a Torque converter problem? Am I talking huge money?!? or something I can fix? The truck has never been mistreated and I hardly romp on the pedal so I can't understand why anything would be wrong with my transmission. I'm desperate! Thank you for any info anyone can provide

 

Why did you start changing parts before getting the fault codes read out? That's going to tell you where to look, stop shotgunning it.

Parts store free scans won't read trans codes, you need to go to a shop that has a high end scanner.

 

Hmm... didn't expect a snide remark such as this...

Where I live there is no reputable mechanic shop. The closest is 30+ miles away and I have not drove nor do I own a trailer to take my truck there. What I DO have is a friendly mechanic that lives near me who works for an oilfield company. He gave me a suggestion and I tried. Please tell me again how is that shutgunning it?

I don't know what is going on, it's hard for me to get it anywhere so before I go out of my way to take the truck 30 miles away from me (without another vehicle) I would like to know if anyone has any knowledge I can try to fix this here at my home...

Don't worry about replying I'm done anyways I'll find a way to get it to a mechanic shop.

 

Well, excuse me!

When you get a computer-detected fault, the proper way to troubleshoot is read out the fault first, not use old school techniques and start replacing parts right off the bat. I'm surprised your friendly mechanic didn't mention this.

Here is a capable scanner, probably the least expensive one available that can read Ford transmission fault codes: