I was just driving on the freeway and the speedometer suddenly dropped to zero and go back up to normal. but my car didn't stumble and run just fine. does anybody know what's wrong with it and how to fix it? thanks.

it's a 1990 fastback with manual tranny.

 

speed sensor may have came loose.

I was driving one day and i was like wtf 0mph. I pulled over and i had spilled trans fluid everywhere for the last 30seconds. Speed sensor was hanging down. Luckly i was close to home.

 

oh. so I should really check my tranny fluid....... well I guess it's time to change anyway. thanks