Strange Little Vibration In OD
My 96 Buick Riv has developed a short duration vibration just as the tranny shifts down from 4th gear to 3rd. Its a very brief (maybe a second or so) winey sounding vibe which disappears quickly. Doesn't occur between the other gears just 4th to 3rd. It also occurs for a longer duration when the car is lugging in 4th gear but not enough to down shift to 3rd. Its not slipping at all and is shifting fine but I'm kinda concerned that this is a symptom of something I should have looked at. Any ideas about this guys?