I have a 2004 silverado 4x4 that I lifted with a superlift fit kit 6" susp. I had it put on around 36000 miles. Every since when the truck is cold in the mornings it makes a roaring noise at 55 to 65 mph for about the first 15 to 20 min. and then it is not as bad. The noise sounds like it is maybe up front but did not do it before lift kit installed. Seems to be getting a little worse. Any ideas what it could be.

What you are describing almost sounds like the clutch for the fan may be going bad. Mine roars like that right after i first start it and start driving but a guy i used to know had a blazer that would do it all the time, but that is cause the clutch was seized. It is something to check into.

well it really sounds like the transfercase or front diff because if i put in 4hi it is not as bad.

I woulda said the fan, too

It sounds like it could be in the front diff. and if I put it in 4hi it doesn't do it, kind of like if the fluid gets warm after 15 or 20 min. it isn't as bad.

There was an issue with some of gm's trucks and their front diff bearings going bad, it is worth looking into and searchingon here for. I know there was a few threads about it.

thanks for input. i hope something i can fix because noise gets old.

I guess my question is what would make that noise just by putting on a lift kit?