Squeaky and vibration

Will just cruising with my foot off the gas my yota 87 pickup makes this wierd squeaky sound and accompanying the sound is a vibration in the floorboard.. This sound and vibration is not present during acceleration nor braking. It could be the tranny since the tranny does not shift properly (engine goes into high revs to get into 3rd and doesn't want to shift.... it goes up to 40 mph fine and then the high rev starts and i have to drop my foot off the gas.. then it goes into 3rd... it is an auto)