Even though gas is pushing 4 bucks a gallon (at least here on Long Island it is) you have to ask yourself this: How much will it cost to do a tranny swap, and how much gas will you have to go through to make that extra 3-4 MPG pay off? That's exactly why I'm still driving my '90 Grand Voyager...sure it's old, and sure a new one will get better mileage...but the '90 has everything I need, and with the kind of driving I do, I'd probably have to keep the next car for 20 years before I even reach the break even point, gas savings wise!