I am experiencing two very strange noises that I can't figure out what they are??? I posted friday about having tranny problems, only to find out that it was due to my tune on my Predator. Now, however, when I start the truck up, it sounds like someone putting air into an air tank. Really weird, only does it when you put it in gear, not while in neutral...

The other one is when driving, at any speed above 10mph, there is a very apparent "whine" that sounds like it is coming from the brake booster area. At 70, it is a very noticable noise, like something trying to turn without fluid in it? Upon deceleration, you can hear it wind down steadily until it dissapears RIGHT AT 10mph. At first I though it was in the tranny, because of the problems that i was having, but after having my wife drive while I listened, it is definatly behind the dash somewhere.

BTW, the brake booster container has a Bosch label on it, and since I bought the truck used, I have a feeling that this isn't an OEM part? Any suggestions would be greatly appreciated!!!

Thanks

 

I have a very similar problem, but mine sounds slightly different. Let me know if there are any similarities. I have 85,000 miles on my 5.4 liter truck, and about 5000 miles ago i noticed a significant whining sound. At first I thought it was some noise coming through my speakers via some short in a speaker wire. However, it now sounds like it is coming from just behind my dash over the transmission. The difference in my story and yours is I notice that it only happens in a certain rpm band, right b/w 1500 and 2000 rpms. I havent checked yet, but I dont think I remember this sound happening when the truck is in park and the gas is depressed. This is starting to worry me b/c I think it may be the tranny. Is this similar, and does anyone know what the problem is and how to fix it?