The "No Power" Saga Continues

J

john dolan

New member
Jun 25, 1998
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>If this is my tranny, why does it "bog down" the engine. It seems to me
>that the tranny is doing it's job of transferring power, it is just that the
>power is lacking. I have followed with interest the recent "no power"
>posts.

Larry...

Interesting story and familiar...

I have a vague recollection of having a similar discussion maybe a year ago
here on the net about this scenario. Was it with you? I can't remember for
sure. There is a lot of experience here on the net with transmissions, so I'm
sure those guys can help.

I remember my transmission acting like yours and I was in denial (telling myself
it wasn't the transmission) because it wasn't slipping . I think someone
here, told me there was a torque converter stall failure mode (or some such
terminology) where the only symptom of transmission failure, in that case, is
lack of power at lower speed. See if this sound familiar... you know what it
feels like in a car when you start off in second rather than in first? Well with
my transmission, it felt like I was starting off in third and with 12000 lbs of
dead weight. (but it never slipped... till the very end after the extra heat
caused other stuff to fail, I think. I put 12,000 miles on it not knowing about
that stall failure mode)

I often found that the only way to get out of some tight spots I had gotten
myself into, was to advance the distributor (giving me more power at low speed)
till I got out and then remember to retard it, so that it would not ping at
highway speed.

I got pretty good at retarding the advance, while under way. (I didn't know they
had sensors and retarders

When the transmission finally died and was replaced, I thought they had tuned the
engine and had given me 2 to 3 times more power than I was used to. I inherited
the coach in that condition (bad torque converter) so I didn't know how it should
act. Maybe someone who really understands these things can help us, and if there
are any differences between the symptoms, be sure and point them out Larry.

I remember groaning through some red lights at the top of hills in Pennsylvania,
because I had learned that I would be backing back down the hill, (also
dangerous) if I stopped. If it is the same situation, you will not believe what
it is like, after it is fixed, Larry. It will be worth 2 to 3 times the cost
whatever it is.

Regards,
John 74 Glacier near Washington DC
 
> I remember my transmission acting like yours and I was in denial (telling myself
> it wasn't the transmission) because it wasn't slipping . I think someone
> here, told me there was a torque converter stall failure mode (or some such
> terminology) where the only symptom of transmission failure, in that case, is
> lack of power at lower speed. See if this sound familiar... you know what it
> feels like in a car when you start off in second rather than in first? Well with
> my transmission, it felt like I was starting off in third and with 12000 lbs of
> dead weight. (but it never slipped... till the very end after the extra heat
> caused other stuff to fail, I think. I put 12,000 miles on it not knowing about
> that stall failure mode)
>
>
> Regards,
> John 74 Glacier near Washington DC

Oh no! John I hope I am not in denial too!. Although I just finished a
8,500 mile plus circumnavigation of the country, without incident and
with really good gas mileage, I felt it is sluggish on start up like you
said and although I felt it may be abnormal, the majority of the time
the behavior is near normal as are the indicators like oil temp of about
170. I also have quick heating of the fluid on hills, up to 230
degrees, where it reaches equilibrium. I did not worry with Mobil-1 in
it and the fluid looks real good, but is one of the symptoms quick heat
up of the fluid on hills, I have always noticed the fluid reached a
toasty 200 plus for a short while on all sizeable hills and on the real
ones, 220-230 out west. Please tell me it aint so. walter bright, 76
GB.
 
>If this is the problem, I will buy you a chicken sandwich in Acapulco.

That is the part we need the expertise of the net for... And I was just trying
to help with the exposure. I think it might be related to some pump inside the
converter that when it fails causes this stall (angle of attack of the fan
blades) kind of stall. Seems to me a *very* reputable transmission shop (or a
friend, or a friend of a friend is needed here, because there should be a way to
diagnosis this from a pressure reading from the outside, I would think.

Hope this helps you get some real help on this... HELP (and I like your chicken
sandwich line

John
 
Guys:

I have forwarded your concerns to Bruce Roe, a Toronado aficionado
extraordinare on the switch pitch transmission and developer of the "fuzzy
logic" controller for it, that Caspro uses on their 6-speed transmission,
for comment.

Will let you know what he has to say once I get a response.

Paul Bartz

From: John Dolan [mailto:jdolan]
Sent: Monday, November 01, 1999 4:02 PM

>If this is the problem, I will buy you a chicken sandwich in Acapulco.

That is the part we need the expertise of the net for... And I was just
trying
to help with the exposure. I think it might be related to some pump inside
the
converter that when it fails causes this stall (angle of attack of the fan
blades) kind of stall. Seems to me a *very* reputable transmission shop (or
a
friend, or a friend of a friend is needed here, because there should be a
way to
diagnosis this from a pressure reading from the outside, I would think.

Hope this helps you get some real help on this... HELP (and I like your
chicken
sandwich line

John
 
>I think it might be related to some pump inside the converter that when
> it fails causes this stall (angle of attack of the fan blades) kind of stall.

Heck Roger Black, might be able to help here... he doesn't have a lot of
time in the left seat in GMCs but he does have a lot of time in Cobras...
Maybe we need a cyclic control on this thing! (is that the switch pitch
Thang?

(walter said)
>but is one of the symptoms quick heat up of the fluid on hills, I have
>always noticed the fluid reached a toasty 200 plus for a short while
>on all sizeable hills and on the real ones, 220-230 out west. Please
>tell me it aint so. walter bright, 76 GB.

I'll bet dollars to donuts there is a faster temperature rise but only if you
do a lot of start and stopping or slow speed climbing (you know really
nursing it) because as I understand this failure, the pump inside or
whatever it is, is not used over about 20 or 25 MPH (depending on your gearing)
and is not needed either, above that speed, so the failure can go 'unnoticed'
except as we have said.

That jives with my experience because if I could keep my speed up, I could go up
some pretty steep hills and it seemed like I had more power, but what it really
was, was that I was turning enough RPM inside the converter that I didn't need to
adjust the angle of attack, is that the cyclic Roger? (or is that the switch
pitch Paul or somebody)

John
74 Glacier near Wash DC
 
Thanks Paul...

Didn't see your response till after I asked for your help...

>>>>>
I have forwarded your concerns to Bruce Roe, a Toronado aficionado
extraordinare on the switch pitch transmission and developer of the "fuzzy
logic" controller for it, that Caspro uses on their 6-speed transmission,
for comment.
>>>>>

John
 
Here is what Bruce has to say.

Paul Bartz

From: bcroe
To: s9d3452
Sent: 11/1/99 3:54 PM

Paul, A "torque converter" at zero to low output shaft speed is capable
of output torque of 2 times (2.5 for switch pitch) what the engine is
putting in. This is acomplished by a stationary set of vanes that
redirect
the oil at low speeds. As speed picks up, force on the vanes decreases
as
does torque multiplication. Eventually the force reverses and the vanes

or "stator" is allowed to freewheel in the other direction. At this
point
torque input to output is 1:1. In a switch pitch the vane angle can
change

If the one way clutch that allows the stator to freewheel breaks, it
may freewheel in both directions. In that case you are at 1:1, all your
starting advantage is lost. Most likely this is the problem. Bruce Roe
 
>Does seem a good comparison, expensive, high maintenance, & more
>fun than sex. Well, maybe more fun, maybe not. Depends.
>Does the GMC have a "Jesus" nut?
>Roger
>http://albums.photopoint.com/j/AlbumList?u=119592&Auth=false

Thanks for the parable Roger...

I see Arch has just added to the knowledge pool...

from my experience here, it is now time to let the power of the net work on
this a bit more... read Arches homework assignment and maybe some other knowledge
will surface. Thanks to all... and thanks for the help on the police action
CBWood. It is all appreciated.

It is hard to believe, but Paul is already back with a response from the the guy
they call extradiniare....

This is getting great...

John
 
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