I have a 2003 f150 super crew 4x4 and every time I hook my trailer and tow about 600 lbs, I get this squeaking sound (sounds like see saw see saw). It sounds like it's coming from the rear u joint area (the u joint seems ok).
It does it real loud when accelerating lightly from a stop and then quiets down the faster you go. It only does it on acceleration and in "Drive". If I put it in neutral and accelerate while driving it does not do it.
It's driving me crazy because as soon as I unhook the trailer it won't do it or does it but not as loud.
Does anyone know what it might be?

 

It probably is a dry U-joint. Just because it seems okay doesnt mean much. The axle loads up and changes angle on acceleration and your other key is that you put it in neutral and took the load off the U-joint. Change the U-joint, fix the squeak.

 

Does the noise speed up when the truck moves faster. Or does the noise always remain the same? How much tongue weight is on the truck when trailering?

 

The noise speeds up the faster I go until it sounds like a constant squeak but not as loud.
You can hear it better when traveling along a curb with the window down.
I have about 60 - 80 lbs of tongue weight.

 

Yea I agree, bad ujoint/s are mighty suspect.

Yea can "feel" good while bolted up in place, tight no play in the caps. You need to remove the shaft to know for sure. Only takes one bad cap, one with dry rusty needles in it to start squeaking. Then in a short time it will begin to chirp and ping with direction changes.

 

I was thinking U joint too but why does it squeak so loud when towing the trailer and hardly nothing at all when driving with out the trailer?

 

Anything I would say as to why, would be theory. Slight angle change of the drive shaft due to tongue weight putting more friction on bad U-joint needle bearings ? Trailer/load weight enough to put more friction on bad U-joint needle bearings? You may be able to duplicate for a short period by accelerating through first gear faster ( applying more load with a slightly heavier gas peddle) no trailer attached. It does sound like U-joint though. But..... Are you sure that its not your trailer axle/bearings that are making the noise?

 

As stated above towing puts more strain on the joints. Mine just started making a slight noise today after a recent tow of a 4100lb fifth wheeler. Even though I couldn't find anything loose I'm going to assume one of them is on its way.
I get the noise while accelerating from a dead stop and it seems to disappear at around 30 mph. It is a very light ticking and I don't feel any vibration but past experience tells me one of them is bad. I have the two piece shaft so it will be twice as much fun.
regards
rikard

 

U-joint replacement time as others have all stated, if you are hearing it without the load of the trailer. Would hate to know you did replace them and the whole tim eit was with your trailer.

Had the same problem for nearly 9 months after doing some sever tugging and towing. If you are still unsure, then put some PB blaster on the driveshaft u-joints. let soak. then repeat. then drive for sometime and you will notice a difference. The angle of the u-joint changes with load, and your are getting that angle that is now exposing the dry needle bearing.

FTE members advised me of this as well, and after disassembling it, the u-joint nearest the differential was shot, the cap fell out since the needle bearings were nothing more than rust.

 

It's definitely coming from the truck.

 

....Best Internet diagnoses sounds like Rear drive shaft U-joints . If the glass is half full, then I would look at that noise as a early warning noise. How nice it would be if every part gave us a pre-failure notification . Gives you a little time to try to further verify that its not coming from someplace else, and get estimates/figure out if your going to try it yourself. I'm a shade tree mechanic and I just did them on my other truck, ( 76 El Camino ) and it was easy. Haven't had my turn on the Fords yet.

 

BFH and being careful not to knock the needles out of place and smash one is the easiest. You can use ball joint/u-joint press to get them in and out pretty easily. They are like any other u-joint I have ever done. Just make sure to get the zerk in the right spot so you can grease it when it comes time.

 

Mabe if it had a zerk in it now, he could try and grease it, but, for the most part, I would drop the shaft and replace it, and check the others while it's down. (It's def the rear u-joint...)

 

Yup, it was the rear u joint.
I attached the trailer and went for a ride but I couldn't get it to make any noise until about 45 mins later and just barely so I dropped the shaft and removed the u joint and at one end the needle bearings were all worn out and rusted. I've changed u joints before but this one was a nightmare.
First the 4 bolts that bolt on the rear end were rusted on and I had to heat them up to remove them.
Then the bearing caps were a nightmare to remove but after using a C clamp, a vice and a very large hammer I managed to remove them and replace the u joints.
I also did the front one but that one was still ok, it was the back one making all the noise.
It took me all day to get it done.

Thanks to everyone that replied.
Also I noticed that I put this in the wrong forum.
Thanks again for helping me out.

 

.....NIce! .yah, I noticed that in your original post. I 'v only been a member & Ford owner for a short time but this group has been a rock solid asset, and a fun place to be for me. I do believe that because of this thread you are now an honorary member of the 87-96 group .