Hey guys, I have an 85 4x4, SR5, manual and over the past month I've been hearing this really horrid screeching/chirping sound which sounds like its coming from inside or very close to my dash board/instrument cluster. It only seems to happen when the truck is cold (i.e. first drive of the morning) and it seems to be connected to my speedometer somehow too. Every time the screech/chirp cuts out my speedometer jumps (about 5mph). It only happens when I'm driving, not at idle, and usually starts somewhere between 20-40mph and has continued up until 70-80mph and can either cut in and out, or stay going constantly for up to 15 miles cruising on the freeway. Only seems to happen the first time I drive the truck for the day, as in, on the way to work but not on the way home 9 hours later, and I'm not using it in between. Has anyone else had this problem or have any idea on what it could be?