I have a 2003 F150 Supercrew with approx. 35,000 kms and for about the last 3 months I have been noticing a shudder in the rear drive train when pulling a trailer and/or a grinding when cornering (with and without a trailer).

I have limited slip (3:73 rear-end), but I had this on my other trucks, and not experienced this before. The dealer has changed the diff. oil, added an additive and told me that is all they can do.
Sometimes it sounds like the rear-end is going to drop off.

Also, when I have the truck in 4 hi, it will go in and out of gear at low speeds or cornering. Once again the dealer has inspected it, changed a "fork kit", and sent me on my way, but it still happens (getting pulled out of snow-filled laneways by GM's is most embarrassing!).

The final remark from the dealer is that since I have some warranty time left, I will just half to wait until there is a complete drivetrain failure.

Pls. respond if you have a similar experience.

 

Did they take it for a drive and hear the noise themselves? If so, it doesn't seem like they can just send you on your way and wait for something to break. Your gonna have to stand your ground a little firmer and "make" them do something to get the noise to go away. Even if it takes a new rearend. There's a reason it's making noise, and it's not good.

Having said that, my old 2wd ranger I used to have had a limited slip rear and before it turned into an open diff., it made groaning noises while turning, especially after a good commute home from work. I dropped a tube of the additive in it and it fixed it for a while but eventually came back. But like I said, it eventually turned into an open axle and the noise almost went away at that point.

Go back down to the dealer and "get-r-done!"

 

I don't know what the warranty left on the vehicle is, but the law is that if you bring to them a problem with the vehicle while it is still under warranty and they can't fix the problem or find the problem then when it gets worse or completely fails they have to cover it. You did what you're suppose to do, and that is let them know before it is serious and more damage occurs. If I were you I would make sure that the dealer noted it and you get a copy of that notation and keep it until it fails. You can then go back in and they have to warranty it.

I know this because I just went through this with chevy on my girlfriends cavalier. They tried to not warranty a drive shaft problem that I told them about and took in for them to fix when it was still under warranty. I had my paperwork where the problem was noted. After that they said no problem and took care of it.

 

I don't know exactly what years it applies to, but there is a tech service bulletin out about the TL chattering. I know it covers the 2000 year TL. The fix is to replace the clutch pack and to shim it 0.010" less. If this TSB applies to the 2003, they should fix it under warranty. They should fix it under warranty anyway, but there is a TSB out on this subject. Ask to see it. The dealer in my home town gave me a copy. I don't know where it is right now.