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Discussion Starter · #1 · (Edited)
Hello everyone.

I just received a 2000 Taurus Wagon ... It's got the Vulcan and the AX4S.

When it's cold, I sometimes notice a lot of 'shutter' under acceleration, which I assume is torque converter related.

Also, after it warms up ... the 1-2 shifts become a little erratic ... feels like it can't decide between 1st and 2nd gear.

I dropped the pan from the tranny and noticed quite a bit of ultra fine dark colored debris and a few tiny slivers of metal on the magnet.

This car only has about 53,000 miles on it.

Could this be the VSS ??? ... or something much worse?

Great forum you guys have here.

Thanks!
 

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Welcome to TCCA!

See if you can get hold of a scan tool that will monitor the VSS PID so you can see if the PCM is getting the correct speed value from the VSS as you drive instead of throwing parts at the car hoping to fix it.

First thing I would do is a complete tranny fluid exchange and new filter (NOT a power flush!). There are instructions on this site. Only takes an hour or 2 to do at home. Be sure to refill with Mercon V only. Modern trannies are very sensitive to fluid quality and correct fluid level.
 

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when you take off does it seem like it is shifting right the the vss is like to ecu but only for the transmission
 

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Discussion Starter · #5 · (Edited)
Welcome to TCCA!

See if you can get hold of a scan tool that will monitor the VSS PID so you can see if the PCM is getting the correct speed value from the VSS as you drive instead of throwing parts at the car hoping to fix it.

First thing I would do is a complete tranny fluid exchange and new filter (NOT a power flush!). There are instructions on this site. Only takes an hour or 2 to do at home. Be sure to refill with Mercon V only. Modern trannies are very sensitive to fluid quality and correct fluid level.

Thanks for the info.

As for the tranny flush ... already done ... fluid wasn't too bad, but it was dirty ... black silt covered the bottom of the pan ... a few tiny slivers of metal on the magnet ... replaced with Mercon V.

I haven't noticed the speedo acting up at all.

Went to Autozone tonight ... no codes showing at all.
 

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Fyi, on the 5-6 vss ive changed out, ive never had a single code and only 1 speedo issue and 1 od off light flashing, but a slipping 1-2 shift after warming up every single time along with some erratic tranny shift points.
 

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Even though the speedo and PCM both get the VSS signal, there seems to be cases where the speedo still works, but the PCM doesnt get the correct VSS signal (maybe speedo will respond to a lower AC voltage signal from VSS than PCM needs, or the PCM is much more sensitive to the waveform of the VSS output??). Thats why I always monitor the VSS PID as one of the first steps when trying to diagnose tranny shifting issues.
 

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Discussion Starter · #8 ·
Even though the speedo and PCM both get the VSS signal, there seems to be cases where the speedo still works, but the PCM doesnt get the correct VSS signal (maybe speedo will respond to a lower AC voltage signal from VSS than PCM needs, or the PCM is much more sensitive to the waveform of the VSS output??). Thats why I always monitor the VSS PID as one of the first steps when trying to diagnose tranny shifting issues.
So should I just go ahead and replace the VSS?

How about the TPS?

Also, this morning I noticed a lot of shutter while turning ... felt like the torque converter to me ... could a bad VSS or TPS cause shutter ???
 

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Personally, I dislike throwing parts at a problem hoping one of the will fix the issue. I myself would not replace the TPS or VSS without monitoring the PIDs for both of them with a scan tool to verify if each part is sending the correct or incorrect data to the PCM.

On the other hand, both VSS and TPS are relatively inexpensive, so if you want to shotgun it, go ahead and replace both and see what happens.
 

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Discussion Starter · #10 ·
Personally, I dislike throwing parts at a problem hoping one of the will fix the issue. I myself would not replace the TPS or VSS without monitoring the PIDs for both of them with a scan tool to verify if each part is sending the correct or incorrect data to the PCM.

On the other hand, both VSS and TPS are relatively inexpensive, so if you want to shotgun it, go ahead and replace both and see what happens.
I'm not too crazy about throwing parts at the problem either.

I am mechanically inclined, but when it comes to scanning codes and the like, I have very little experience.

What is a PID?

What type of scanner do you use?
 

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PID = Parameter IDentifier. PIDs let you look at the data the PCM is receiving from the sensors, etc. They give you a look "inside" the PCM to see what it is doing. I have 2 scan tools. An Actron 9180 (or something like that) handheld which reads codes, does freeze frame data, IM readiness, and monitors many common PIDs, but by no means all. It has a graphing mode also. For more in depth troubleshooting, I have a PC (laptop) based Autoenginuity (spelling) scan tool with the enhanced Ford diagnostic package. True bi-directional communication with PCM, runs on demand tests, monitors hundreds of PIDS, does mode 6, and tons of other stuff. That one was pricy... around $400 if I remember correctly, but has paid for itself many times over.
 

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Discussion Starter · #12 ·
PID = Parameter IDentifier. PIDs let you look at the data the PCM is receiving from the sensors, etc. They give you a look "inside" the PCM to see what it is doing. I have 2 scan tools. An Actron 9180 (or something like that) handheld which reads codes, does freeze frame data, IM readiness, and monitors many common PIDs, but by no means all. It has a graphing mode also. For more in depth troubleshooting, I have a PC (laptop) based Autoenginuity (spelling) scan tool with the enhanced Ford diagnostic package. True bi-directional communication with PCM, runs on demand tests, monitors hundreds of PIDS, does mode 6, and tons of other stuff. That one was pricy... around $400 if I remember correctly, but has paid for itself many times over.

Looks like a great tool ... Order Online ... pricey indeed ... $250 for the basic PC package, plus another $200 for the Ford expansion.

The Ford dealer should be able to read these codes, right?
 

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Any $50 scanner you get can read codes, but codes dont tell you the whole story. The PIDs are what really tell you what is going on. My Actron scanner, which I seem to remember I got off Ebay for $140 or so years back is a great scan tool, and has worked very well for solving problems 90% of the time. It shows (and graphs) PIDS like VSS, TPS, ECT, IAT, fuel trims, FLI, and a whole bunch of other very useful PIDs. The PC based scan tool, which has near dealer level functionality with the enhanced package, has really only come in handy for those "really weird" problems that come up every now and then. The Actron, as with most other low to mid priced tools, only reads "P" codes, while the PC based tool reads C, B, and U codes as well, which are very useful for diagnosing ABS issues, PATS issues, and other non powertrain related issues.
 

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Discussion Starter · #14 ·
Any $50 scanner you get can read codes, but codes dont tell you the whole story. The PIDs are what really tell you what is going on. My Actron scanner, which I seem to remember I got off Ebay for $140 or so years back is a great scan tool, and has worked very well for solving problems 90% of the time. It shows (and graphs) PIDS like VSS, TPS, ECT, IAT, fuel trims, FLI, and a whole bunch of other very useful PIDs. The PC based scan tool, which has near dealer level functionality with the enhanced package, has really only come in handy for those "really weird" problems that come up every now and then. The Actron, as with most other low to mid priced tools, only reads "P" codes, while the PC based tool reads C, B, and U codes as well, which are very useful for diagnosing ABS issues, PATS issues, and other non powertrain related issues.
I think an Actron needs to be in my toolbox.

Back to my shifting problem .. the 1-2 rough shift usually only happens at moderate to light throttle ... if I rev to 2500 or 3000 rpm it shifts fine.

It's probably either the TPS or VSS ... at least I hope it's that simple.
 

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Discussion Starter · #15 ·
** UPDATE **

I replaced the VSS in my 2000 Wagaon AX4S

The tranny shifts nice and smooth now.

Thanks everyone, for your help.
 

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Discussion Starter · #16 ·
** UPDATE **

Well, I thought the VSS did the trick.

However... the old rough shift from 1-2 is back.

It does shift better than it did prior to new VSS .. it's not as indecisive as it was ... but it's still rough.

I may check the Throttle Position Sensor next.
 
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