Hitch groans loudly when turning

Different recommendations from different manufacturers, I guess.  Curt makes it very clear that the trunion pockets be cleaned and re-greased after (or before) every tow.

Although everything above is undoubtedly true, there is one hitch that absolutely requires lubrication each and every tow.

Yup, it was the sway bar.  Didn't tighten it as much this last trip out and it made a huge difference ... thanks!

Thanks everyone!  I am positive now that it is the friction anti-sway bar, and something we'll just get used to.  Ours clearly states on the label on it to never lubricate the bars, and I'll take another look to see if it has any direction on how much to tighten it.

I guarantee it is your friction bar.  In 26 years of towing I've never found it necessary to lube the ball.  That would be an easy mess if you did, or you have to go to extra lengths to keep it from getting all over you and the TV (when removed from the receiver).

Someone mentioned cleaning the bar, I had to do that once in a while by taking a file to the bar.  Also read your bar's instructions to see how tight to make it.  The one I had for our popup had them printed right on the bar, and I think it was supposed to be turned no more than 1 full turn after initial contact.  While you can lube the mini balls on either end (I wouldn't and didn't, they don't make any noise) you never want to lube the bar.

If you have an Equalizer or E2 you have to be careful about what you lubricate.  You can lube the pockets on the head where the spring bars mount, but you should not lubricate the bars themselves where they rub on the L brackets.  That is where the anti-sway friction is created.