Is worth while to spend $600 - $700 for a used transmission? The car has 128,000. Breaks are good, body OK, engine OK.
Where would the transmission be coming from? Is that the price for the whole deal – install and labor included – or just for the part?
When I was pricing used transmissions for a 1990 Geo Prizm last year, the multiple places I called said I’d have to call around to parts places but could expect to pay $300-400, plus $400-500 for labor for the transmission shops to put it in. But they also couldn’t vouch for the quality of the transmission I might get, which seemed pretty risky to me. If I’d done the repair, I probably would have gotten a rebuild for about twice that money ($1500-1800) knowing I’d have a warranty…and knowing, too, that the maintenance history of that car was very good, and that I’d be unlikely to get a similarly maintained car for the cost of that trans.
That was a much older car, but with similar mileage. It’s certainly possible that a Taurus transmission will be more in demand (therefore more expensive) and probably more readily available, since your car is newer.
But others on this site will have much more expertise than me.
I’d suggest a rebuilt transmission, which should come with some sort of warranty, rather than a used transmission, which is a gamble.
If the car is solid there’s no reason not to replace the transmission and keep driving it.
Unless you’re tired of the car, wish for something newer, and can afford to buy another car. These are things we don’t know.
Only you can decide whether or not it’s “worth it.” It’s a personal decision.