A-904 TC fill quandry
 

On a A-904, like the 727, the torque converter doesn't fill in park,
only in neutral, which is a really good safety feature, if you stop
and think about it. I notice after sitting a couple of days, if the
car is started in park and moved directly to either rev. or for.,
there's an initial "bump," not too hard, but firm. When it is first
shifted to neutral to fill the converter, initial engagement is
smooth. Once the car's been warmed up and driven, further engagements
are perfect. To proove that this may be part of the bumpy engagement
when cold, I put the cooler supply line into a pan and listened as it
was filled....sounds like a small amount of air is burping out of the
converter when first shifted from park to neutral.

Is this common, or is there a leaky converter check valve in play
here? Any "easy" fix for same, or just the nature of the Torqueflite?

A-904 TC fill quandry
 

"DeserTBoB" > wrote in message
...
> On a A-904, like the 727, the torque converter doesn't fill in park,
> only in neutral, which is a really good safety feature, if you stop
> and think about it. I notice after sitting a couple of days, if the
> car is started in park and moved directly to either rev. or for.,
> there's an initial "bump," not too hard, but firm. When it is first
> shifted to neutral to fill the converter, initial engagement is
> smooth. Once the car's been warmed up and driven, further engagements
> are perfect. To proove that this may be part of the bumpy engagement
> when cold, I put the cooler supply line into a pan and listened as it
> was filled....sounds like a small amount of air is burping out of the
> converter when first shifted from park to neutral.
>
> Is this common, or is there a leaky converter check valve in play
> here? Any "easy" fix for same, or just the nature of the Torqueflite?

The condition is perfectly normal and is often called "morning sickness".
There is no converter check valve so converter leakdown will occur when the
car isn't running.

There are kits made by TransGo and Sonnax that allow the converter to refill
in Park but the cheapest fix is to get in the habit of making the initial
startup in Neutral instead of Park.

A-904 TC fill quandry
 

On Tue, 29 Aug 2006 11:42:36 -0700, "John Kunkel" >
wrote:

>There are kits made by TransGo and Sonnax that allow the converter to refill
>in Park but the cheapest fix is to get in the habit of making the initial
>startup in Neutral instead of Park. <snip>

Actually, the layout having no drive from the converter's turbine in
park is a good, well thought out engineering idea, so I'll keep it.
Now I have to train the wife for a week on how to do that! It took a
month to get her to release the parking brake AFTER applying the
service brake to prevent parking pawl binding from being "loaded,"
which I hear is also common on RWD Chryslers and anything else, from
my experience. At least they don't wind up popping into reverse, like
the pre-1969 Fords did!

Thanks for the reply, John.

Now if I could only figure a good retrofit to knock off that TCC while
climbing a grade in direct drive, life would be serendipitous

A-904 TC fill quandry
 

look out fellas- next DeserTBob will be telling you to teardown the
entire top end of the motor, and pull the oil pan and pump, when the
problem is a stuck thermostat

Add to kill file
 

A-904 TC fill quandry
 

DeserTBoB wrote:

> On Tue, 29 Aug 2006 11:42:36 -0700, "John Kunkel" >
> wrote:
>
>
>>There are kits made by TransGo and Sonnax that allow the converter to refill
>>in Park but the cheapest fix is to get in the habit of making the initial
>>startup in Neutral instead of Park. <snip>
>
>
> Actually, the layout having no drive from the converter's turbine in
> park is a good, well thought out engineering idea, so I'll keep it.

You don't understand what John's talking about. The change that the
TransGo kit makes to the valve body that allows the TC to fill in park
has nothing to do with "drive from the turbine." It has to do with
whether or not fluid from the pump (which is NOT driven by the turbine)
gets dumped straight back to the pan (factory configuration in "park")
or gets circulated through the transmission cooling system as it does in
neutral. The idea of *not* circulating the fluid when in park is the
only stupid thing the factory did with the Torqueflite transmissions. It
has no advantage, and several disadvantages (slow or no filling of the
TC in park, no heat rejection in park, less lubrication of the
disengaged clutch packs in park, etc.).

A-904 TC fill quandry
 

Steve wrote:
> DeserTBoB wrote:
>
>> On Tue, 29 Aug 2006 11:42:36 -0700, "John Kunkel" >
>> wrote:
>>
>>
>>> There are kits made by TransGo and Sonnax that allow the converter to
>>> refill in Park but the cheapest fix is to get in the habit of making
>>> the initial startup in Neutral instead of Park. <snip>
>>
>>
>> Actually, the layout having no drive from the converter's turbine in
>> park is a good, well thought out engineering idea, so I'll keep it.
>
> You don't understand what John's talking about. The change that the
> TransGo kit makes to the valve body that allows the TC to fill in park
> has nothing to do with "drive from the turbine." It has to do with
> whether or not fluid from the pump (which is NOT driven by the turbine)
> gets dumped straight back to the pan (factory configuration in "park")
> or gets circulated through the transmission cooling system as it does in
> neutral. The idea of *not* circulating the fluid when in park is the
> only stupid thing the factory did with the Torqueflite transmissions. It
> has no advantage, and several disadvantages (slow or no filling of the
> TC in park, no heat rejection in park, less lubrication of the
> disengaged clutch packs in park, etc.).
>

Hi...

Anyone know if that also applies to my 94 lhs 3.5?

Better to start and idle in neutral than in park?

Thanks, and take care.

Ken

A-904 TC fill quandry
 

On Wed, 30 Aug 2006 09:24:40 -0500, Steve > wrote:

>DeserTBoB wrote:
>
>> On Tue, 29 Aug 2006 11:42:36 -0700, "John Kunkel" >
>> wrote:
>>
>>
>>>There are kits made by TransGo and Sonnax that allow the converter to refill
>>>in Park but the cheapest fix is to get in the habit of making the initial
>>>startup in Neutral instead of Park. <snip>
>>
>>
>> Actually, the layout having no drive from the converter's turbine in
>> park is a good, well thought out engineering idea, so I'll keep it.
>
>You don't understand what John's talking about. The change that the
>TransGo kit makes to the valve body that allows the TC to fill in park
>has nothing to do with "drive from the turbine." It has to do with
>whether or not fluid from the pump (which is NOT driven by the turbine)
>gets dumped straight back to the pan (factory configuration in "park")
>or gets circulated through the transmission cooling system as it does in
>neutral. The idea of *not* circulating the fluid when in park is the
>only stupid thing the factory did with the Torqueflite transmissions. It
>has no advantage, and several disadvantages (slow or no filling of the
>TC in park, no heat rejection in park, less lubrication of the
>disengaged clutch packs in park, etc.). <snip>

OK, thanks for that. I'll just idle in neutral until it's time to
pull the valve body, and then add a kit. I checked this out on
TransGo's site, and there was evidently a common shop "cure" of
drilling a small hole in the pressure reg. to allow the TC to fill in
park (and thus give cooling and lubrication,) but that makes TC
drainback a bigger problem, so I'll just use John's neutral cure for
now.

A-904 TC fill quandry
 

Ken Weitzel wrote:

> Steve wrote:
>
>> DeserTBoB wrote:
>>
>>> On Tue, 29 Aug 2006 11:42:36 -0700, "John Kunkel" >
>>> wrote:
>>>
>>>
>>>> There are kits made by TransGo and Sonnax that allow the converter
>>>> to refill in Park but the cheapest fix is to get in the habit of
>>>> making the initial startup in Neutral instead of Park. <snip>
>>>
>>>
>>>
>>> Actually, the layout having no drive from the converter's turbine in
>>> park is a good, well thought out engineering idea, so I'll keep it.
>>
>>
>> You don't understand what John's talking about. The change that the
>> TransGo kit makes to the valve body that allows the TC to fill in park
>> has nothing to do with "drive from the turbine." It has to do with
>> whether or not fluid from the pump (which is NOT driven by the
>> turbine) gets dumped straight back to the pan (factory configuration
>> in "park") or gets circulated through the transmission cooling system
>> as it does in neutral. The idea of *not* circulating the fluid when in
>> park is the only stupid thing the factory did with the Torqueflite
>> transmissions. It has no advantage, and several disadvantages (slow or
>> no filling of the TC in park, no heat rejection in park, less
>> lubrication of the disengaged clutch packs in park, etc.).
>>
>
> Hi...
>
> Anyone know if that also applies to my 94 lhs 3.5?
>
> Better to start and idle in neutral than in park?
>
> Thanks, and take care.

I'm pretty sure it does NOT. The 41TE/42LE transmissions are pretty much
unrelated to the older ones. Hydraulically, they have a good number of
simplifications to the basic system. Some good- like full circulation in
"park." Some really BAD, like no variable line pressure regulator- they
run full pressure 100% of the time which is one reason they can run so
hot and are so hard on fluid. The giveaway is that the instructions tell
you to check the fluid in PARK on those, which implies that full
circulation occurs in park.

A-904 TC fill quandry
 

"Steve" > wrote in message
...
> DeserTBoB wrote:
>>
>> Actually, the layout having no drive from the converter's turbine in
>> park is a good, well thought out engineering idea, so I'll keep it.
>
> You don't understand what John's talking about. The change that the
> TransGo kit makes to the valve body that allows the TC to fill in park has
> nothing to do with "drive from the turbine." It has to do with whether or
> not fluid from the pump (which is NOT driven by the turbine) gets dumped
> straight back to the pan (factory configuration in "park") or gets
> circulated through the transmission cooling system as it does in neutral.
> The idea of *not* circulating the fluid when in park is the only stupid
> thing the factory did with the Torqueflite transmissions.

Well said. The open leak at the manual valve in the Park position is a
holdover from the old pushbutton shifter days when there was no Park
position in the quadrant and the engine had to be started in Neutral.
After 40+ years it's hard to figure why Ma Mopar has chosen to ignore this
condition when the aftermarket has recognized it for years and done
something about it.