Hello,

I have a 2002 F-150 Supercab 4x4 sport. It has a 5.4 engine and automatic transmission with 71,000 miles. About 400 miles ago I started to notice a vibration when the transmission goes from overdrive back to 3rd. It doesnt happen in any other gear changes at the moment. Usually when I start up a fairly steep hill and the transmission tries to down shift it will have the vibration lasting just a second. When it does this, it sounds like you run off the edge of the road and hit the grooves. I have done nothing to the transmission. Most of the people I talked to in the past said the tranny fluid didn't have to be changed. The logic always was that if it needed to be changed, they would have put a drain plug in the pan from the factory. I have never had any transmission trouble before with any of my trucks and I don't tow anything. I guess I should have changed that fluid like the maintenance schedule said to.

My question is: What exactly is the trouble with the transmission? Could it be the torque converter? Will a fluid change help at this point and possibly some lucas tranny treatment? I also heard of putting some kind of limited slip differental conditioner into the tranny to help the torque converter. Is that really a good idea?

Thanks for the help guys,

Wayne

 

I think I will just try a fluid and filter change without any additives and see how it goes. If it doesn't help I may try the lucas in it.

 

It probably is the torque converter shuddering. New MERCON V fluid will usually fix it, unless it's gone on long enough to damage the friction material in the clutch.

Here's a way to change all of the fluid. Just changing what's in the pan won't fix it.

https://www.ford-trucks.com/article/...nsmission.html

 

Thank you Casey.

I was going to change all the fluid including the converter. If I am going to tear into it I might as well do it right. It has been doing it for about 400 miles, but it doesn't do it all the time, so I am in hope it hasn't messed anything up yet.

Thanks again.

 

Update:

I changed the transmission fluid and filter. Man that stuff is hot after a 50 mile drive at 80mph!!!! Anyway. I tried to follow the guide that is linked in this thread.

Since I was changing the filter, I went ahead and started by dropping the pan and cleaning everything out. The fluid was kind of a dark red and looked like metalflake paint. I cleaned the pan and magnet real well and discarded the stopper that was laying in the pan. I then installed the new filter and put the pan back in place.

Now to remove the drain plug to drain the torque converter...... I never found a drain plug on it. My truck is a 2002 and the seatbelt latches in the truck when I bought it had a sticker on them that said "2003 model only" on them, so it is a late in the year 2002 model. From what I understand in trannys built in 2001 they quit putting drain plugs on the torque converter. I put everything back together and decided to use the line removal to get the fluid to pump out of it.

The guide states that it will be the line to the back of the transmission. As luck would have it my lines are one on top of the other. Neither one is farther back on the tranny. Plus with the heat shield they are hard to get to. I traced them to the front of the truck and found a place to unhook it at the tranny cooler on the passenger side of the truck. I had no idea if this was the return line or not so I put the bucket under the cooler just in case and put the line in the bucket. I started it and nothing happened. Ahhhh I forgot to put the new fluid in the tranny. I put 6 quarts into the pan and tried again. After a few seconds the fluid came out of the cooler so I did have the return line.

I let it run until I had approximately 6 quarts in the bucket and stopped. I reinstalled the cooling line and added another 6 quarts to the tranny.

At this point I decided to leave well enough alone. I went for a drive and then checked the fluid. While driving I still noticed the vibration. I figured I would give it a day or two and see how it went. Now it doesn't seem to have the problem. I guess it just took driving it a little to get the new fluid circulated around and work where it needed it.

I know I still had about 2 quarts of old fluid in the tranny, but I was unsure if I would know the clean from the dirty while it was running out. I will probably do it again in a few thousand miles and use this as a kind of "cleaning cycle".
I will be sure to get some extra fluid to make sure if I don't catch it at the right time I will have plenty to put back in. Plus I will have the 2 quarts I didn't put in it this time.