3 days ago I was starting to leave the house, and I noticed from take off to about 30mph, there was a loud vacuum sound, does this have anything to do with the vacuum pump itself? Or is it something else?

 

I sincerely doubt you would be able to hear a leak from the vacuum pump over the noise of the engine. I would rather think it was the fan clutch that was engaged momentarily. This can happen when the truck is cold an first started up, usually goes away within a minute. Do you have gauges? (Boost, EGT).

 

I. Have boost and pyrometer.

 

Were your EGT's above normal?

 

No. They were normal

 

My guess would definitely be the fan clutch then. It makes a definite swooshing sound!

 

Thank you mishkaya

 

it could also be a torn innercooler boot