Torque converter early lock up

I have a '01 GT that has the shudder problem, i.e. the TC lock up engages
too early. Any ideas how to fix it? Is there an easy way to get the PCM
updated so that it engages only at higher speed/RPMs? Advice is much
appreciated.

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On Tue, 09 Dec 2008 15:19:16 -0600, "JSB" > wrote:

>I have a '01 GT that has the shudder problem, i.e. the TC lock up engages
>too early. Any ideas how to fix it? Is there an easy way to get the PCM
>updated so that it engages only at higher speed/RPMs? Advice is much
>appreciated.


I'm not sure what the connection is between teh shudder problem and
the early lock up. My 99 locks up too early as far as I'm concerned
(and sometimes immediately unlocks) but never shudders. I've never
seen a "fix". if you find one, please post it.

As far as I understand from a Ford mechanic, the TC locks up too early, and
then, upon taking your foot of the gas, unlocks and locks up again, hence
the shudder, together with a sort of clunking sound. Only happens when TC
locks up b/w 30-45mph in OD, no problems at 50+ mph. Any thoughts?

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On Thu, 11 Dec 2008 19:08:01 -0600, "JSB" > wrote:

>As far as I understand from a Ford mechanic, the TC locks up too early, and
>then, upon taking your foot of the gas, unlocks and locks up again, hence
>the shudder, together with a sort of clunking sound. Only happens when TC
>locks up b/w 30-45mph in OD, no problems at 50+ mph. Any thoughts?


The shudder I've always heard talked about was a part throttle
shudder, not a foot off the gas shudder. But you may be getting more
or less the same thing I am, which I think it mainly an error in how
they programmed the computer. It's all computer controlled and I
think what happens is that based on all the sensor inputs the computer
tells it to lock up, then after it's locked that changes the load/rpm
relationship of the engine, which changes the sensor readings, which
tells the TC to unlock. I suspect the only fix is to get used to it.
Possibly a transmission rebuild would have some effect but it's a
pretty expensive diagnostic approach.

"Ashton Crusher" > wrote in message
...
> On Tue, 09 Dec 2008 15:19:16 -0600, "JSB" > wrote:
>
>>I have a '01 GT that has the shudder problem, i.e. the TC lock up engages
>>too early. Any ideas how to fix it? Is there an easy way to get the PCM
>>updated so that it engages only at higher speed/RPMs? Advice is much
>>appreciated.
>
>
> I'm not sure what the connection is between teh shudder problem and
> the early lock up. My 99 locks up too early as far as I'm concerned
> (and sometimes immediately unlocks) but never shudders. I've never
> seen a "fix". if you find one, please post it.

I agree. my 06 GT has a shudder problem also. But is not the TC. My
Shudder
is wheel hop.

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Torque converter early lock up
by Ashton Crusher > Dec 11, 2008 at 09:10 PM

On Thu, 11 Dec 2008 19:08:01 -0600, "JSB" > wrote:

>As far as I understand from a Ford mechanic, the TC locks up too early,
and
>then, upon taking your foot of the gas, unlocks and locks up again,
hence
>the shudder, together with a sort of clunking sound. Only happens when
TC
>locks up b/w 30-45mph in OD, no problems at 50+ mph. Any thoughts?


The shudder I've always heard talked about was a part throttle
shudder, not a foot off the gas shudder. But you may be getting more
or less the same thing I am, which I think it mainly an error in how
they programmed the computer. It's all computer controlled and I
think what happens is that based on all the sensor inputs the computer
tells it to lock up, then after it's locked that changes the load/rpm
relationship of the engine, which changes the sensor readings, which
tells the TC to unlock. I suspect the only fix is to get used to it.
Possibly a transmission rebuild would have some effect but it's a
pretty expensive diagnostic approach.


Thanks, appreciate the reply. Funny thing though is that it only does this
below ~45mph in OD. Wouldn't it make sense to have the PCM reprogrammed to
only engage TC lock up >50mph, for example?

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On Fri, 12 Dec 2008 17:02:39 -0600, "JSB" > wrote:

>
>Car and Auto Forums > Ford - Mustang > Torque conv...
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> Torque converter early lock up
>by Ashton Crusher > Dec 11, 2008 at 09:10 PM
>
>On Thu, 11 Dec 2008 19:08:01 -0600, "JSB" > wrote:
>
>>As far as I understand from a Ford mechanic, the TC locks up too early,
>and
>>then, upon taking your foot of the gas, unlocks and locks up again,
>hence
>>the shudder, together with a sort of clunking sound. Only happens when
>TC
>>locks up b/w 30-45mph in OD, no problems at 50+ mph. Any thoughts?
>
>
>The shudder I've always heard talked about was a part throttle
>shudder, not a foot off the gas shudder. But you may be getting more
>or less the same thing I am, which I think it mainly an error in how
>they programmed the computer. It's all computer controlled and I
>think what happens is that based on all the sensor inputs the computer
>tells it to lock up, then after it's locked that changes the load/rpm
>relationship of the engine, which changes the sensor readings, which
>tells the TC to unlock. I suspect the only fix is to get used to it.
>Possibly a transmission rebuild would have some effect but it's a
>pretty expensive diagnostic approach.
>
>
>Thanks, appreciate the reply. Funny thing though is that it only does this
>below ~45mph in OD. Wouldn't it make sense to have the PCM reprogrammed to
>only engage TC lock up >50mph, for example?

It would make sense in a normal world but I'm guessing that kind of
change would potentially affect the EPA Mileage numbers which would
mean they would have to rerun some series of tests at great expense.
So they just say "screw it". There was a company advertising an
electronic gizmo that would delay TC lockup but they never brought it
to market for the 99 and newer vehicles. They did have such a gizmo
they sold for older, less computer intensive, transmissions.

It would make sense in a normal world but I'm guessing that kind of
change would potentially affect the EPA Mileage numbers which would
mean they would have to rerun some series of tests at great expense.
So they just say "screw it". There was a company advertising an
electronic gizmo that would delay TC lockup but they never brought it
to market for the 99 and newer vehicles. They did have such a gizmo
they sold for older, less computer intensive, transmissions.

------------------------------

Thanks man, I'm afraid you're right.

I've posted a take from another Mustang forum, although these guys talk
about the older, pre-99 series Mustangs. Don't know if it's applicable,
but thought it's interesting nonetheless...

********


Torque converter clutch shudder in AOD-Es in 94 through 98 Mustangs is a
know problem. Ford has issued about three or four different Technical
Service Bulletins regarding the issue, but no recalls!

At any rate, the symptom is a shudder coming from the transmission (feels
kind of like you are driving over a series of those little speed bump
strips) when you are driving at “light to moderate throttle� (the
words in the TSBs).

The problem as stated by Ford is two-fold. The first cause is a breakdown
of the friction properties of the older Mercon IV and earlier transmission
fluid due to heat build up. The second cause is undersized friction plates
in the torque converter clutch in the torque converters on all AOD-Es from
94 to 98. The combination of these two problems results in a
grabbing-slipping, grabbing-slipping, etc. of the torque converter clutch
during shifts at light to moderate throttle. As soon as you “get on
it� the shudder goes away!

I had this problem on my stock 95GT. I followed all the advice in Ford’s
TSBs. Replaced the tranny fluid with the new synthetic Mercon V and
installed an auxiliary tranny fluid cooler. For the first 2,000 miles
after that, I had no more shudder, so I thought it was fixed. But then it
came back. (The Ford TSBs say that if the symptom returns within 10,000
miles you have to replace the torque converter because the clutch is just
too far gone.)

At any rate, I wasn’t about to go through that expense yet, and I heard
about a product by LubeGard called, “Dr. Tranny’s Instant Shudder
Fixx�, that was supposed to work some magic on the tranny and stop the
shudder. It’s a small 5� long red tube of what looks like regular
tranny fluid, but its actually a friction modifier that acts on the torque
converter clutch friction surfaces. About $10.00 to $15.00 bucks a tube
depending on where you get it.

I put one tube of that stuff in my transmission, cycled the gear shift
lever through the gears, backed out of the driveway, and drove off. No
shudder!!! Gone!

So, for $10.00 bucks or so, I’d say give it a shot. It’s only 2 oz. of
fluid so you won’t have to drain any out before adding it. Just add it to
what’s in there now.

If you can’t find the stuff at a transmission shop, here’s their web
site. You can buy it direct from them on line.

www.lubegard.com/automotive/index.html

From their home page, go to Transmission Products, then to the link for
Dr. Tranny’s Instant Shudder Fixx.

After about another 2,000 to 3,000 miles the symptoms returned. After
that, even another tube of this stuff would not stop it. The problem is
that the torque converter clutch friction plates are just too
burned/glazed to recover.

You’ll eventually have to replace your torque converter.

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you might try a custom tune and ask them to tune it so that it doesn't lock
up a lower rpm speed. I know that you can get custom tunes from several
vendors.
Charles
"C Ducote" > wrote in message
...
>
> "Ashton Crusher" > wrote in message
> ...
>> On Tue, 09 Dec 2008 15:19:16 -0600, "JSB" > wrote:
>>
>>>I have a '01 GT that has the shudder problem, i.e. the TC lock up engages
>>>too early. Any ideas how to fix it? Is there an easy way to get the PCM
>>>updated so that it engages only at higher speed/RPMs? Advice is much
>>>appreciated.
>>
>>
>> I'm not sure what the connection is between teh shudder problem and
>> the early lock up. My 99 locks up too early as far as I'm concerned
>> (and sometimes immediately unlocks) but never shudders. I've never
>> seen a "fix". if you find one, please post it.
>
> I agree. my 06 GT has a shudder problem also. But is not the TC. My
> Shudder
> is wheel hop.
>