Transmission or torque converter?

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Falcon_LS

Falcon_LS

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2001 Mercury Grand Marquis with a Ford 4R70W. When I fired her up this morning, there was a strong shudder until the rpms dropped and everything went back to normal.

As I was driving, I noticed the car would start to shudder when accelerating, which I thought was quite weird. Then when I was coming home this evening, the transmission randomly downshifted and I lost forth gear. At one point, I released the gas and it upshifted into forth all by its own but downshifted as soon as I touched the gas. When I stopped at a light, I had to give it a bit more gas to get it moving, almost like it was stuck in third or something.

When I got home, I revved the engine in neutral and the shuddering was ridiculous to the point where I could almost feel it in my teeth. I revved it up to 2,500 rpm I think.

Does this sound like the TC is toast? Thanks!
 
Almost sounds like it has a bad coil. Our F350 had a coil go out and it acted similar but it never set the check engine light. Missing 1 cylinder really makes them feel down on power.
 
Originally Posted By: Miller88
Almost sounds like it has a bad coil. Our F350 had a coil go out and it acted similar but it never set the check engine light. Missing 1 cylinder really makes them feel down on power.


Yes this ^^, check the engine , it's common to mistake a transmission issue if you have loss of power and performance .
 
How many miles are on it? It sounds like the transmission if it is not the coil. there is no need to monkey with the transmission if it is still doing OK.

What is the situation on auto repair in Kuwait? I am sure you have some decent local shops.

On my Beast, I have about 186,000 miles now. I am noticing that steady, but slight, vibration when the transmission is cold and I take it out of Park or Neutral. It is increasing over the past few months and it shifts rough when cold. It will need a rebuild sooner or later. Maybe in 20,000 miles, maybe 100,000. So I am already asking around for cost. The local Stealership wants about $4.000.00. But my main mechanic will do it for $3000.00. Another will want $1500.00, and there is a well-respected transmission specialist in El Monte who will do it for $1250.00. Downtime for the last guy will be three days. With transmission repairs it seems that specialist shops are the cheapest and fastest, and stay away from the dealerships (stealerships).

All these guys say it will not strand me, it will gradually just get worse till I decide it is time to do the job.
 
Originally Posted By: Falcon_LS
2001 Mercury Grand Marquis with a Ford 4R70W. When I fired her up this morning, there was a strong shudder until the rpms dropped and everything went back to normal.



You should not get trans shudder when sitting still. Check the entire ignition system from coil to plugs.
 
Originally Posted By: Doog
Originally Posted By: Falcon_LS
2001 Mercury Grand Marquis with a Ford 4R70W. When I fired her up this morning, there was a strong shudder until the rpms dropped and everything went back to normal.



You should not get trans shudder when sitting still. Check the entire ignition system from coil to plugs.


Right answer...
 
Originally Posted By: TFB1
Originally Posted By: Doog
Originally Posted By: Falcon_LS
2001 Mercury Grand Marquis with a Ford 4R70W. When I fired her up this morning, there was a strong shudder until the rpms dropped and everything went back to normal.



You should not get trans shudder when sitting still. Check the entire ignition system from coil to plugs.


Right answer...
+ 1
 
Unless something is seriously broken in the torque converter and it's out of balance, nothing in the transmission should be felt at idle in neutral.

I agree with the diagnoses of a spark/fuel issue.
 
You also said it stopped above a certain RPM? When coils start to fail and get farther along, they'll work above a certain RPM. Also, Ford couldn't (and still can't) make COP work without blowing coils all the time.
 
Thanks for the input! It's looking more and more like the TC - I used a scan tool to check for misfires and the count is zero for all eight cylinders, even when it's vibrating to knock your teeth out. Will need to drop the pan and confirm.

If it is out, it's quality money for a quality unit, but I will go new instead of remanufactured. Maybe an 11.25" for a CVPI will be a good choice.
 
Any significant trans issue (ie one that would cause a shudder) in an OBDII Ford would probably also result in a flashing "O/D OFF" light.

No codes at all for a noticeable issue is weird. My truck throws a light when the gas gauge is off, I think it would go ape [censored] with a trans issue. My Explorer flashed the O/D OFF light when I soaked a speed sensor in mud (with no drivability issues, normal shifting).
 
Yes, I find it very strange that there are no codes. As I was stuck in third, I was keeping an eye out for the green flashing O/D OFF light. It never appeared.
 
Originally Posted By: Falcon_LS
Thanks for the input! It's looking more and more like the TC - I used a scan tool to check for misfires and the count is zero for all eight cylinders, even when it's vibrating to knock your teeth out. Will need to drop the pan and confirm.

If it is out, it's quality money for a quality unit, but I will go new instead of remanufactured. Maybe an 11.25" for a CVPI will be a good choice.


When our F350 lost a coil, there were no codes, no check engine light. The garage had to pull the coils individually to see what one was the problem.

Makes no sense considering it's OBDII
 
Originally Posted By: Falcon_LS
Yes, I find it very strange that there are no codes. As I was stuck in third, I was keeping an eye out for the green flashing O/D OFF light. It never appeared.


Did you inspect all of the wiring going to the trans? How is the fluid level?
 
Last edited:
Originally Posted By: Miller88
When our F350 lost a coil, there were no codes, no check engine light. The garage had to pull the coils individually to see what one was the problem.

Makes no sense considering it's OBDII
Same thing happened to my wife's Marauder. Would skip in higher gears with moderate throttle. No CEL. Replaced the coil on cylinder #3 and good as new.
Originally Posted By: Falcon_LS
Maybe an 11.25" for a CVPI will be a good choice.
Agreed.
 
Originally Posted By: Falcon_LS
Thanks for the input! It's looking more and more like the TC - I used a scan tool to check for misfires and the count is zero for all eight cylinders, even when it's vibrating to knock your teeth out. Will need to drop the pan and confirm.

If it is out, it's quality money for a quality unit, but I will go new instead of remanufactured. Maybe an 11.25" for a CVPI will be a good choice.


To check for actual misfires logged and in real-time, you need access to Ford's "mode 9" (IIRC) information. You'll only get a misfire to show up under OBD2 if there have been several thousand of them, enough to trigger the CEL.

Went through this with the Expedition when #8 coil went out.
 
Originally Posted By: OVERKILL
Originally Posted By: Falcon_LS
Thanks for the input! It's looking more and more like the TC - I used a scan tool to check for misfires and the count is zero for all eight cylinders, even when it's vibrating to knock your teeth out. Will need to drop the pan and confirm.

If it is out, it's quality money for a quality unit, but I will go new instead of remanufactured. Maybe an 11.25" for a CVPI will be a good choice.


To check for actual misfires logged and in real-time, you need access to Ford's "mode 9" (IIRC) information. You'll only get a misfire to show up under OBD2 if there have been several thousand of them, enough to trigger the CEL.

Went through this with the Expedition when #8 coil went out.

He said he is reading misfire count so i assume he is accessing it with a scan tool capable of mode 6.

Edit: He has brand new Standard Red box made in USA coils, plugs and injectors.
I know that doesn't guarantee one cant be defective.
He did have a lot of problems with an ECM tune that went all weird also.
 
Last edited:
Originally Posted By: Trav
Too late to edit.

This is interesting. Ford apparently doesn't support true misfire counting in mode 6 on this car.

http://www.motor.com/article.asp?article_ID=553


Looks like I reversed the 6 to a 9, thanks Trav
smile.gif


And that doesn't surprise me at all. So he really has no idea if he's got a misfire or not
frown.gif
 
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