A reader asks: My 1996 Ford Taurus with the 3-liter V-6 engine has an intermittent problem with its transmission. On cold days, it seems to work fine, but on warm days, it seems to slip when I engage Drive. It doesn't slip if I move it directly to low gear. Am I looking at a new gearbox or should I be looking at a new car entirely?
The automatic transmission has always been the weak spot on the Ford Taurus, so you have good reason to be concerned. But before any decision is made to perform major transmission work, have a competent mechanic do the following:
1) Check the level and condition of the transmission fluid.
2) The powertrain control computer should be scanned and any code stored investigated.
3) If circumstance warrants, the automatic transmission pan should be removed and the filter checked for possible clogging or metallic particles, indicating internal transmission wear. If nothing is found in these basic controls, you'll need to replace the transmission.
The reason the unit operates better in cold vs. hot weather is that transmission fluid is thicker when cold and thinner when hot. So a problem such as a cracked forward-clutch-applying piston (a common problem on older Taurus transmissions) would be more apparent when warm than cold.
BIG EXPENSE. As to putting it in low gear manually, you bypass a lot of the hydraulic circuitry when you do that, which gets you around the problem.
If you choose to repair it, you should have a quality rebuilt transmission installed -- either a Jasper or Ford factory unit. Any other needed components, such as the crankshaft rear main oil seal, should also be replaced at this time. Think about having an auxiliary transmission oil cooler installed to prevent future problems as well. You should expect to pay between $2,800 to $3,400 for the job -- it's a big one.
As to the economics, a car is an expense, not an investment. You will never recoup the money spent on the transmission when you resell the car. So what you have to weigh is, how much more life can you expect out of the resuscitated old car (probably many years) vs. how much you will spend on a new one.