How do you change a speed sensor on a 95 Lexus ES300?

[Julia]

My check engine light is on and sometimes the "o/d off light blinks. The rpm's jump around while driving. The engine light code says the speed sensor is bad. If someone could give me some advise as the best procedure to fix the problem. Where is the speed sensor and how hard is it to fix. Is it something a shade tree mechanic can do, or does it need to go to the shop. The mechanic shop will charge me an arm and a leg. I just cant afford it.

[faisalrafique]

better go to the dealer it is not expensive