Switching from flex fan to OEM steel fan.

[Mullins72Custom]

Over the past several months I've had an issue with truck over-heating while ideling over 10 mn ect. I HAD a flex-fan without a shroud so I decided to install a shroud. It didn't help as wished, so I swapped my flex fan out for my friends OEM steel fan/clutch. Instillation went fine, and my over heating problem was solved! BUTTT as I drive around 40 mph or > it squels like a lost pig. Belts are tight, fan is attached tight. I used some dove soap to coat the belt, but the squelling continues! Any advice? Is the new fan throwing something off?