Weird noise

My husband has a 2006 2.7L manual 5 speed.
He recently just changed the u-joints. Yesterday he called and said his truck is now making a weird noise. When he came home we went for a drive. I stuck my head out the window and could hear a flapping noise coming from the rear. Kinda sounded like when you would put a card in the spokes of a bike. But only does this at low speeds.
Any ideas?

 

Did he grease them? I know, silly question, but needs to be asked.

 

One or more may not be properly seated, also.

 

Yes watched him do it.
Not a silly question. People forget to do stuff

 

If the snap rings went on, they should be properly seated.

It could be the dust shield on the carrier bearing.

That's about it for ideas from me. Good luck!

 

Thank you

 

Maybe heat shields loose?

 

The neighbor kid put a playing card on your rim with a clothespin?

 

Ok, seriously...jack the rear up and spin the tires to see if you can hear it. Much easier than driving around with your head out a window...and I'm saying do it with the engine off and tranny in neutral. Make sure the fronts are blocked securely.

 

That's what he is planning to do when he gets home. He's hoping it's just the u-joints.
Also already looked for cards....lol

 

rock in a tire tread ?

 

I was going to say that too...check tires for rocks or screws/nails. Makes a nice clicky noise.