[swapped]

Hey guys,

I have a 99 Ford Taurus SE with the DOHC engine.

I wanted to get some thoughts on my trans issue.

When i drive the car it shifts fine, once in a while it kind of bangs when i let go of the gas or when i push the gas pedal after coasting. When i accelerate fast, let off the gas, and then accelerate again (sometimes) it will slip like crazy and finally catch with a bang.

Now i was thinking that I might have a bad (ish) TPS sensor becasue i noticed that when driving, if i take the car out of drive (put in neutral) the rpms will climb pretty high - this depends on speed.

I disconnected the tps and the trans only slipped a bit when cold (first couple of shifts) and then it just shifted hard - as expected with the tps disconnected.

So what do you guys think? The car has 140k and it has a trans cooler and i have been changed the fluid at 40k 80k 100k 120k and about to change it agian. This problem has been here for quite some time and i thought that the trans was going, but it has not gotten a bit worse in the last two years, which leads me to believe that it might not be a bad trans, just a bad sensor / solenoid somewhere.

Any thoughts?

Also, has anyone had any suceess with additives such as lucas transmission fix or perhaps running a can of seafoam prior to fluid flush?

Thanks

 

[egiroux]

Hey guys,

When i accelerate fast, let off the gas, and then accelerate again (sometimes) it will slip like crazy and finally catch with a bang.

Now i was thinking that I might have a bad (ish) TPS sensor becasue i noticed that when driving, if i take the car out of drive (put in neutral) the rpms will climb pretty high - this depends on speed.

I disconnected the tps and the trans only slipped a bit when cold (first couple of shifts) and then it just shifted hard - as expected with the tps disconnected.

This problem has been here for quite some time and i thought that the trans was going, but it has not gotten a bit worse in the last two years, which leads me to believe that it might not be a bad trans, just a bad sensor / solenoid somewhere.

Any thoughts?

Also, has anyone had any suceess with additives such as lucas transmission fix or perhaps running a can of seafoam prior to fluid flush?

Thanks

Sensor issues should not cause slipping. Sounds like an internal issue. Don't put in any addatives with 'seal conditioners' in them.

 

[swapped]

Thanks for the response. I might be defining slipping wrong.

My thought process with the tps was that perhaps it was giving an incorrect signal and upon the accelerade, let off, accelerate the trans was just simply not commanded to the correct things and therefore was in and out of gear / between gears....not sure that makes any sense.

Could anyone confirm that when driving along at about 45-50 mph and putting the transmission in neutral that their car revs to about 4 or 5 k? I dont think this is normal - no other car ever did it.

Thanks

 

[thecurrent]

When i drive the car it shifts fine, once in a while it kind of bangs when i let go of the gas or when i push the gas pedal after coasting. When i accelerate fast, let off the gas, and then accelerate again (sometimes) it will slip like crazy and finally catch with a bang.

Most transmissions will act a little strange if you are driving like this and catch the transmission in the middle of up/down shifting or trying to figure out what you are wanting it to do.
Your best bet before anything else is to check it for codes. Even if the check engine light is not on there may be some codes stored in memory.

Take the car to an Autozone or Advance and have them do a free code scan on it. See what that turns up and go from there.
Worst case you may need to take it into a reputable Ford dealer or a repair facility that you trust. It may cost about $80-$100 for a full diagnostic to be performed but you will at least find out whats wrong before replacing things.
They can also check and monitor your TPS output and other sensors related to transmission operation.

Here are a couple TSB's I pulled from AllData that may or may not be of any help. Can't link it but you can look these #'s up on this site.

99-18-4 Harsh 3-2 downshift/shudder on acceleration
03-12-3 TCC TORQUE CONVERTER CLUTCH NOT ENGAGING AND/OR DIAGNOSTIC TROUBLE CODES (DTC) P0741 OR P1744

Hope this helps.

 

[swapped]

car has no codes. I just got codes pulled not too long ago when i got the light on. the only code that came up was related to vacuum by the gas tank.

 

[wjc]

If you suspect the TPS, you can backprobe the return signal wires (see a wiring diagram for your car's color codes and pin positions) with an analog multimeter. With key on 9engine doenst have to be running, move the throttle slowly htrough its full range and watch the needle for smooth sweeping with no dropouts. Sudden changes mean a deadspot in the TPS contacts and it needs to be changed.

If the TPS is OK its prolly time for a trans rebuild. Sorry.

 

[sheila]

If tps fails to cure your ills, i would slap on an $18-20 vss. A known failure item on 99 tecs.

 

[swapped]

thanks for the help guys! I will have to check it out. Can't say i have an analog meter, but can see how seeing that on a digital one would be difficult. I was thinking of doing that exact thing the other day but i would have done it with a digital one........probably would have missed it if it was bad anyway.

I think i replaced the vss once. I know there are two sensors on the trans that tell speed (i think one is vehicle speed and the other shaft speed). my speedo went to zero and trans wouldnt shift. The part stored didn't have any so i just ran over to the junk yard and ripped one out. quick fix and it was back up and running.

I might try a new one of those also, but i also fear that the trans is on its last leg.

 

[danhasenauer]

Sensor issues should not cause slipping.

Haven't had a VSS go bad on you yet, eh?

 

[sheila]

+1 on the above. I have changed 4-5 vss on 98-99 tecs and all exhibited tranny shift point probs. (esp. the infamous 1-2 slip after warming up). None had cels and only 1 had speedo issues and the green od off light flashing.

 

[sheila]

Not saying a bad vss is your prob., but they can sure cause a myriad of driveability issues.