Like Cammed said. You would be surprised how much a simple sensor can mess up a car. It probably won't be a cheap 5 dollar sensor though. I haven't seen a seen a sensor cheaper than 15 bucks since my 83 pick for a oil temp sensor which pretty much just superglued to the block. But it shouldn't be more than 120 for a sensor for that car... If they still make it. car parts get discontinued a lot and unless it's popular model, aftermarket companies won't pick up production of the part. At which point that sensor now becomes a whole new transmission just because a new or rebuilt transmission WILL have that part on it. at which point it has just jumped to about 950... I'll be optimistic for ya.