hey guys. i have a 98 audi a4 quattro. the check engine light has been on for a few years now. the code reads that its a speed sensor. the guy i bought it from said that the tranny is slipping because of this sensor. it slips between 2nd and 3rd gear and between 3rd and 4th gear. it does the same thing every time when accelerating. ive gotten pretty used to it and drive it as is. all the other gears work fine. it hasnt got any worse and it hasnt gotten any better. i just want to know if any body has had this same problem or knows what could be wrong. any info would be greatly appreciated. thanks.