2000 3.8L at 19MPH changing from 2 shift to 3 shift, downshift to 1.

[rmendez]

Hello I have a problem with my Windstar 2000 3.8L and I am wondering if anyone can help me. The problem is at 19 mph shifting from 2 to 3 the rmps surge to 3000 and is like the transmission downshift to 1. This happend only after the van get the normal temperature. Cold works perfect. But when is at normal temperature and I see getting 19mph I realese de gas pedal, then shift perfect. I already change the TSS Turbine Shaft Sensor and the OSS output shaft sensor. The Neutral Safety Switch was replaced like 6 month ago. Please give your advice.

[Windstartled]

Is the ABS light on?

[wiswind]

Neutral safety switch seems to be high fail around your year.
I would try to read the codes at the OBDII port.
In the USA, many auto part stores will do it for you for FREE (make sure to ask for the actual numeric code).
I don't know about where you live.

The other thing that can cause strange shifting issues is the Vehicle Speed Sensor (VSS).
This is mounted on the back side of the transmission case.......right above one of your catalytic converters.
It gives your speedometer the value of vehicle speed AND it tells the computer (PCM) how fast you are going.
If this part fails, the computer does not know how fast you are going.....so it does not know how to tell the transmission what gear to be in.

The VSS is a simple part, held in by 1 little bolt......with an electrical connection and (depending upon year) maybe a mechanical connection for the speedometer cable.
This would make replacement simple except that the location is such that is is hard to get to.
When my VSS failed, I was on a mission trip with my youth group.......and I had the repair done for me.
The mechanic told me that he was working "by feel"......in other words....he could not see the part...but was reaching up from under the vehicle and feeling the part.
He also told me that it is common for him to get the wrong part when he order/picks up the part....so he sets the old part next to the new part and makes a comparison between the 2 before he installs the new part..
The actual part is not expensive........but...as I have mentioned......the replacement process is a pain.

[rmendez]

Yes, ABS light on.

[rmendez]

Are the VSS a different part from TSS or OSS I already change both. And the neutral safety switch was replace like a year ago. The netral safety switch is from Autozone. I scan last week in Autozone and the only codes that come are 171 and 174, that I know what it is and I will repair lat because for me is more important the shifting problem.

[wiswind]

If you changed the VSS, you would remember it.
It is above a catalytic converter.
The TSS is located on the driver's side of the vehicle, next to where the driver's side drive shaft comes out of the transaxle.....this measures the speed of the shaft coming OUT of the torque converter, which is NOT the vehicle speed.

[Windstartled]

Originally Posted by rmendez

Yes, ABS light on.

This may very well be the root of your troubles. Like Wiswind says above the VSS sends speed info to the PCM which then manages shifting accordingly. But the VSS itself obtains speed data from the ABS wheel speed sensors either front or rear, depends on the year. If one of the ABS sensors is dead then the speed as reported by the VSS is inaccurate, and this triggers wild shifting. I had the same problem as you, replacing the dead ABS sensor fixed it.

[rmendez]

How I know, which of the four abs speed sensor were dead?

[Windstartled]

Originally Posted by rmendez

How I know, which of the four abs speed sensor were dead?

You need to unplug each sensor and test resistance with a digital multimeter. Healthy sensor will read between 1 and 2 ohms, usually around 1.8 ohm. A reading of zero or very high value means its dead.

You don't have to remove the wheels to do this but it's much easier if you do. Start with the front wheels, sensors there are more prone to failure.

[phil-l]

If the ABS light is on, check your ABS sensors and the related connectors and wiring first. Here are pics of my ABS checks:

http://good-times.webshots.com/album/559769331GYPtlJ

However, there's a well-known failure that often happens on '00 (and other years - but I'm only familiar with '00) ABS electronic control modules. I replaced the electronic portion of m ABS module - and have enjoyed 4+ years of dependable ABS service since then. Here are pictures of my ABS electronic module replacement project (there are also notes with most of the pictures):

http://good-times.webshots.com/album/575113025YrtncQ

One thing has changed since I replaced my electronic module: There are now ways to have your module repaired for far less money than it cost to replace mine. Go to eBay and search on "Windstar ABS" and you'll see some examples of this service. While I haven't used a repaired module, I know of others who have used this approach on other vehicles, and have been pleased with it.

[Windstartled]

The ABS electronic control module is indeed troublesome on many second-generation Winnies and this affects ABS performance. But the shifting issue described by the OP would not be caused by an ABS module failure as it is not actually related to braking. What we call "ABS sensors" are wheel speed sensors that send speed data to both the VSS and the ABS module. The OP's problem has to do with what is being sent to the VSS. Obviously a bad wheel speed sensor will also prevent ABS from working correctly but that would be less noticeable.