I would like to remove and install a new speed senser for a 91 cavalier station wagon.My speedometer is running off and on. There seems to be a clip on top that holds it to the tranny case on RH side of tranny but I can't see any bolts or screws around senser .A mechanic told me that they sometimes seize .I am working underneath car on ramps and am having difficulty seeing and reaching senser and would like to avoid costs related to a possibly seized senser being removed by shop. Information on how to remove and replace senser would be helpful, thanks.