2002 F150 Screw Lariat 4x4 (4R70W)
Well, I bought this truck a little over a month ago. I didn't notice on the test drive, but from day 1 it has had a slight chatter/shudder when driving really slow (5mph) steady in traffic. Almost like driving over really small speed bumps. It also does it at about 40 mph. Took it to a transmission shop and they drove it around and said that it feels like the torque converter is trying to lockup when it's not supposed to. Something about a potential "cross leak" or something like that. Anyway, he says there's something definetly wrong.

Anyone else's doing the same thing? I had the COP's checked...all good. Replaced all the spark plugs w/OEM spec motorcrafts, new PCV valve, cleaned EGR, had Ford do a Fuel induction cleaning service (cleans EGR, TB, upper intake, ports, etc, etc), new air filter, cleaned MAF, new fuel filter, full tranny flush-filter-new fluid, serviced rear & front diff & tcase, and ran a can of seafoam through the tank.

So...it's definetly not a tune-up issue.

Anyway, it's got 67k miles on it, and is covered by warranty until 88k miles, so that is good.

Your thoughts?

 

I've got an '02 S'crew w/5.4 2wd and have had a "hesitation" in the engine for the last 40K miles. The mechanics have told me to just wait until it gets worse. I now have 94K miles and it is about the same (they can't figure it out as it doesn't have any "codes" showing). That being said, the local Ford dealer said that they could put a "black box / trip recorder" on it so when it does "act up" it would capture a "data picture" of what was going on. After all this time and being out of warranty, I'm just getting used to it! You might check with your dealer and try for the "recorder", as a fix. Good luck

 

Trans shudders can hide behind ignition problems and vice versa...I know you said you had the coils checked, but that's not to say that one isn't intermittently breaking down under load. The VDR (Vehicle Data Recorder) like retired2001 mentioned is a very good idea, when it starts acting up, you hit the trigger button and it'll capture relavent PIDs at the time of the fault so the dealer can examine it and see what's going on. If I were working on it, I'd do a coil stress test and power balance test as well just to be double sure to eliminate any ignition concerns. Been there, done that, got burned plenty of times by coils breaking down under load.

Torque converter shudder isn't necessarily a bad thing, in that it won't cause any immediate failures, but it will gradually get worse (if it is the torque converter).