I have a 2001 F-150 4.6L 4x4 with an automatic transmission and I believe something is wrong with my torque converter. I have searched this site and I believe I have a good understanding of what is wrong, but i want to be sure because I am going Elk hunting next weekend, and don't want anything bad to occur. This only happens in low RPM's, and when accelerating slowly to about 45-60 mph, my entire truck shakes (like I am driving over rumble strips, or a dirt road) for a very short time (1/8 sec-3/4) and it is sometimes a long duration, or sometimes barely noticeable. If it happens and I tap on the brake(just enough to activate the brake lights) while keeping my foot on the gas, my truck downshifts and a couple seconds later (when it shifts again) the problem reoccurs. This makes me think of torque converter lock-up. I also know that I have low ignition/misfire in cylinders 1 & 5 (I don't know if this is the problem, but I did read on this site somewhere that this could be the problem). The problem has been happening for about 2 months. After it happened the first time, I replaced the tranny fluid and the filter. The problem was immediately reduced, but was still there. Then it disappeared after a few weeks, and finally came back in the last week. Any thoughts of what I should do? What could I be looking at in the future (i.e. new TC/Tanny?) Also my cousin (a mechanic) recommended Dr. Tranny Shudder Fix as a quick possible solution, what do you think of this product?

Thanks all,
And I hope everyone is ready to feast on that thanksgiving turkey

 

Misfire will cause what you are feeling. So will torque converter clutch shudder.

I recommend fixing the misfire. Misfire over time can destroy the catalytic converter, and that is expensive to replace.

When you changed the trans fluid, how much fluid was changed? There are different methods of changing the fluid, and not all of them change all of the fluid. If you didn't change at least 12 quarts you only did a partial change, which is why you only had a partial fix.

I don't know anything about that additive.

 

Change your spark plugs and be prepared to change one or more coils. Use only Motorcraft plugs in that engine.

 

I can't remember, but 12 quarts of fluid sounds about rite. I am almost positive I drained it all, even the TC. It looks like I am going to be replacing my coils and plugs first. While I am at it, I am going to replace all the coils and not just the ones for cylinders 1 & 5. Should I use Motorcraft coils as well? Those are the kind I was probably going to get anyway.

 

Exact same thing, considerably cheaper:

http://www.ebay.com/itm/New-Visteon-...5bc1a1&vxp=mtr

 

How do these look? Bottom description says that the part brand is Motorcraft, but seem too cheap to be real.

http://www.ebay.com/itm/BEST-QUALITY...52fcf5&vxp=mtr

 

Those are not Motorcrafts, they are generic Chinese replacements. The only Ebay sellers I trust for generics are Global Automotive and Uneek Supply. The Visteons I linked are real OEM's.

 

Ok, thanks. I will order the coils now and see if it fixes my problem.

 

was your problem fixed? i have the same issue on my 98 4.6

 

Try a set of spark plugs.

 

Ok, after several weeks of torment with my life (waiting for the coils, dealing with finals for college, showing up for my Elk hunt on the wrong weekend, and then not getting an Elk on the correct weekend) I finally got my coils and Motorcraft spark plugs in the mail. I replaced all of the old spark plugs and ignition coils with the new ones. After looking at my old spark plugs, Cylinder 1 was having a problem. The plug had a small chunk taken out, and it looked a little burnt compared to the rest. Unfortunately I still have the problem, but my truck does run smoother than before. Anyway, what should I try next?

Again, thanks everyone!

Also, looking into this further (internet) and talking to someone else about their 97-03 F150 with the 4.6, this seems like a common problem. The guy I talked to was a kid that worked at O'Reily and he said the problem (For him) is something that he has been having for almost 2 years. He tried that Dr. Tranny Instant shudder fix (just like what my cousin recommended), and he did notice the problem was quickly reduced, but eventually came back, and he reuses the product every few months. The way he described it seemed like his problem was alot worse than mine. I hope that little bit helps anyone that comes across this post.

 

dont put that snake oil in there! fix it properly. First off, how many miles were on the tranny when it was serviced? if it had over 100k before the first service, you may have done more harm than help. Also, post a pic of the damaged plug.

 

The spark plug on the left is the only bad one (cylinder 1), every other one looked like the one on the right. This is also just after about 8k miles with these spark plugs. I replaced the tranny fluid and filter at about 128,500 miles, and I just rolled over 130,300. I think it has been serviced before because I did NOT find any kind of Factory O-ring thing in the pan. I got the truck at about 116,000 miles, and I do not know when or how often the tranny was serviced.

 

UR burned spark plug if of the correct heat range is probably due to a lean condition. Intake manifold lead or injector filter/screen clogged.

 

After spending alot of time trying to figure out what is wrong, I suddenly had the thought "Hey, maybe I should look at the color of the tranny fluid". Sure enough, after a couple of months with new fluid, the fluid is already discolored a little. I already have a friend that said his shop could get me a new tranny and TC installed with a 2 year warranty for $1300. But I am probably just going to keep this one until it gives out.

Thanks for the help everyone!
If someone still has any suggestions, let me know.