I own a 1998 Ford Taurus SEL with the small V6 and automatic transmission.

I am having the following problem.

When ever you slow the car up to below approx. 30 miles per hour then push the
Accelerator to resume normal speed, the transmission drops from drive to first gear
Giving quite a jerk.

This does not happen all the time, but probably around 40% of the time.

The car has 123k miles on it, and the transmission fluid is changed every 35k, with the fluid just again being changed.

I have had the car to 2 different transmissions shops with each one driving the car with
The computer monitor hooked up. Both times the car dropped to first as described, but the computer registered no errors.

The first shop suggested that a motor mount was bad, but my repair shop says that the mounts are OK.

The second shop suggested that a throttle position switch in the air intake was the problem, so I had the switch replaced. The problem is still there.

Anybody have an idea as to how to solve this problem.

Dave

The problem could be with your preventive maintenance program. I have a 2000 Taurus, with the 3.0L Duratec Engine, and AX4N transmission. I hope you have been dropping/cleaning the pan and changing the filter every 35,000 miles (which should be no more than 30,000 miles), not just using a fluid exchange machine. These transmissions generate quite a bit of crud between changes. I suspect varnish is developing on the servos. I only use Amsoil Universal Synthetic ATF or Mobil 1 Multi-Vehicle Synthetic ATF in my AX4N and change the fluid and filter every 25,000 miles. It's best to do a complete drain, including the torque converter. My Taurus gets driven hard in the Texas heat and shifts flawlessly. Automatic transaxles are electro-mechanical marvels that are more involved than engines these days. They are the weak link in vehicles and need to be carefully maintained. I recommend you only use a full synthetic Mercon V rated ATF. They will keep your transmission much cleaner, cooler, and shifting like new (especially in extreme temperatures) for years of hassle-free driving. The flow characteristics of full synthetic ATFs are vastly superior to regular Mercon V and I would change your fluid again, this time using Mobil 1 Multi-Vehicle Synthetic ATF ($5.68 per qt. at WalMart). This will more thoroughly clean your transmission and likely eliminate your downshift problem.

Install a B&M transmission drain plug in the pan to make it easier next time to change your ATF.