I have a 2002 F-150 FX4 Supercab with the 5.4L engine and an auto transmission. The tranny dipstip says MerconV fluid and the door sticker says "U".

I had the transmission flushed for the first time at 100,000 miles, after having the pan dropped two or three times prior. I heard about the possibility of that knocking stuff loose, but didn't listen based on the advice of the shop I have used previously with success.

The transmission is doing the "rumble strip" thing on occasion when I accellerate hard from overdrive and it shifts down. I also occasionally hear the "clunk" that I understand to be no big deal and can be fixed by lubricating something (slip yoke maybe? anyway, not tranny related).

I checked the tranny fluid today and found black crud on the dipstick. Each time I put it down and pulled it back up, there was more of it on the tip. I got less and less with each "dip". I drove it twice now and still get a little bit with each "dip", but not much. It looks a little bit like dirt ... small particles clumped together.

I now have 122,000 miles on the truck. Tranny fluid is roughly 22,000 miles old. The crud worries me quite a bit, as does the rumble strip shudder. I can mostly eliminate the shudder by carefully accellerating (gently) on the highway, so while I figure it's a bad sign for thee tranny I figure I can at least make it last with careful driving as there are no other issues.

I suppose the crud was knocked loose with the flush and/or is being generated by the shudder. What is your advice on how to proceed? Should I flush it immediately? Or should I drop the pan and replace the filter immediately? Any additive I should use? Would Amsoil fluid help or be a bad investment given the potentially short life of the transmission? I can only figure that doing nothing is a bad idea.

Thanks very much for your help!

John

 

I got impatient and decided to drop the pan, clean it out, and change the filter. I did so this afternoon. The magnet was absolutely covered with gunk. I cleaned it up, but the rest of the fluid actually looked pretty good. I replaced the filter replaced about 4.5 quarts of fluid with Mobil 1 synthetic.

I drove it about 20 miles at varying speeds. The shifting is actually much improved and I couldn't replicate the shudder/rumble strip noise I heard previously. So that's a good thing.

The potentially bad thing is that I'm still getting crud on the dipstick. I'm wondering if there isn't just a little bit of corrosion in the tube. It looks OK, but who knows. In any case, here's hoping I made a good call today.

Feedback/comments still appreciated! Thanks.

John