I did a search but have not found any similiar squeaking problems like my 99L is making. It is not a constant but repetitive squeak that increases with rpms. It doesnt squeak when im in park or neutral, but definetly in gear. It seems to be coming from lowom passenger side of truck. I thought it was tranny related but today when it was running and in park i turned steering wheel to locks and it started squeaking, so this would rule out the trans. and related to being under load.
Is it one of my belts or idler pulleys? It has been doing it for awhile. it went away once for nearly 600miles but has recently came back and is annoying the hell out of me, and sounds embarrasing in traffic.

 

what size upper pulley do you have???? when is the last time you changed belts???
what mods do you have???

 

the truck is completely stock. I have had he truck since 2005 and I have never replaced the belts

 

try replacing the belts and check your idler pulleys

 

I had an intermediate squeak for about 20k about a year, and that is how long it took me to find the problem.

I replaced both belts twice (different brands) then the idler pulleys, and then replace the power steering pump, then I replace the blower’s belt tensional arm, in addition I replaced the water pump, I also went out and purchased the belt tighting additional pulley under the blower snout, still no cigar!

I was going nuts and was beginning to doubt my mechanical abilities, so as desperate act I decide to check my upper 2 lbs pulley, and guess what the Upper Pulley had backed out about 1/32 to 1/16 from the snout, this is after it being on for about 40K, I retighten it and the squeak was gone…

The belts edge was misaligned which was causing the noise!! I have had no problems ever since, and to boot I have several slightly used belts along with a bunch of used parts!

Hope this helps!

 

as far as the belts go there is two right? is the accessory belt the same found on a regular 5.4l engine? meaning can i go to my nearest autozone and get one? And for the supercharger belt what brand is good and where is a good place to get one? thnxs!!