Re: [ihc] Limited slip additive in automatic trannies?

[Colin M Rush <salmineo@xxxxxxxx>]

I have forwarded this note onto Rick Allison at A&A, so hopefully I will
have some outside info on this by a guy who knows more about it than any
of us.  Here are my thoughts, tho.
1.        Limited-slip additive has been around for almost as long as the
727 I would venture.  Why has this never been tried before?  I am
guessing because it either does not work, or makes no noticeable
improvement.  It sounds good in theory, but a properly working trans
should not need this.  I see no mention of this in my MoPar Performance
catalogue, which makes me think that the factory, which has a lot more
engineering background than most of us, does not recommend this as a
viable upgrade.
2.        Why would a person have such a problem with foaming?  The
filter is submerged and almost touching the bottom of the pan.  If
foaming is so bad that it extends to the entire amount of oil, either you
are low on fluid, or are spending an inordinate amount of time in a
high-incline situation so that all of the oil is in the tailshaft
housing.  Another reason I can see is that the trans is too full, so the
rotating assembly is beating the fluid into a froth.  If you have foaming
problems, address the source first.  If you cannot fix it that way, then
get a deeper pan.  It will alleviate the foaming problems, and will give
you cooler fluid as a side benefit.  If anti-foaming agents were the way
to go, then why has nobody thought of it before?  Like above, I find no
mention of it in my MoPar Performance catalogue, while I do see a listing
for a deeper pan.
3.        Regarding the clutches slipping and failing, the clutch
friction materials themselves are not designed to provide the friction
that causes the clutches to hold.  That is done by tension of the fluid,
and the friction materials are sort of a binder or sponge to hold the
oil.  When the clutch is applied, the fluid is squeezed out of the
friction material and from between the material and the reaction plate. 
As the clearance is reduced, the fluid starts to shear, and it is at that
point that the clutch begins to apply.  Eventually the clutch grabs ahold
of the reaction via the tension of the fluid, and at that point the
friction material is touching the reaction plate.  Under extreme load
conditions, the clutches may slip, and that is where having good friction
materials  comes into play.  Better papers give better wear at high
temperatures before glazing, burning, or wearing down.  Once the paper
glazes or burns, then its ability to hold and release fluid is
compromised, and the clutch slips more and more, eventually wearing down
to the steel substrate.  I think that using limited-slip fluid may just
be a mask for symptoms of other things, like low oil pressure, or worn
out clutches, or an improperly assembled trans.  If everything works
right, they should not need it.
4.        If MoPar transmissions hate Dextron, then why do they call for
it on the dipstick?  Again, the factories knew what they were doing.  I
have heard that the late-model trucks have issues with it, but my
understanding on that is that the problem is related to convertor clutch
operation and wear, which is something that IHC products do no have.  I
have heard that the late-models are supposed to use either the factory
fluids to prevent convertor clutch failure, or a type of Toyota fluid. 
Both are dealer-only items, and expensive, but they are supposed to work.
 The rest of the components used in the late-model 618/518/500 units are
virtually identical to the IHC units, except for the convertor clutch and
the overdrive unit.  Just go with what the factory said, which in our
case is Dextron.  You can use Type F if you are in some sort of street or
competition application, but Dextron is much more available at the gas
stations, so use that for ordinary everyday use.
5.        Driving style is the biggest cause of transmission problems I
have seen.  Just because it can go fast, is built for performance, or has
all of the heavy-duty super-throw-me-down parts does not give you license
to abuse your car/truck/engine/transmission under the guise of 'skilz'. 
If it keeps breaking, lighten up, and re-examine how you do things.  Most
of the time, your 'skilz' are not netting anything in terms of speed or
response.  Unless you like dumping money into it and fixing things all
the time.  I dunno, some folks are funny that way.  And others just do
not listen to what their peers are telling them.
-Colin

Date: Thu, 25 Mar 2004 09:52:53 -0600
From: "Dennis Bernth" <scoutdude@domain.elided>
Subject: [ihc] Limited slip additive in automatic trannies?
 
Group-
Besides the general digest, I directed this question to Greg H. and
Colin,
since they seem to be somewhat gurus on this stuff. Through a friend, I
ran
across a website where a guy is proposing to add Mopar limited slip
additive
to his automatic transmission, along with Mopar anti-foaming additive.
Here is
a paste of the first part of his page, with a brief explanation;
Well, many people have asked me for more info on the "fluids additive
package"
that a certian performance company sells (they will remain nameless
because
this is not info I want to use against them) for the Dodge trucks with a
tranny shift kit.  I purchased a Trans-Go shift kit from said supplier
and
when I was ordering it I was told of the "fluids additive package" and
decided
to go for it. The kit cost me 15 bucks, plus 15 bucks for "hazardous
materials" shipping! As soon as the shift kit arried I found that I had
bought
a bunch of fluids that are easliy obtainable from Mopar Performance and
your
local Dodge dealer! I spend 30 bucks where I could have spend 9! So here
you
can find out what the fluids are, what they do, and you don't have to pay
the
extra 15 bucks for "hazardous materials" crap...
 
Anyway, there are two fluids in this kit, one is the same Sure Grip
additive
in a 4 oz bottle you would put in your Sure Grip rear end; weather it be
in
your older muscle car with an 8 3/4 rear end, or your new Dodge Ram with
its
new style Sure Grip. The other is an 1 oz bottle of Anti Foaming agent
used to
prevent foaming in certain applications such as smaller high performance
engines, some transmissions, and even in some rear ends prone to high
load.
Here is what he has to say about older transmissions, like ours;
I see no reason that this "kit" cant be used in a completely stock tranny
in
the newer Rams, or even in much older muscle cars which use the same
basic
tranny design. (Look in a Factory Service Manul from the mid to late 60s
for
the internals of a 727 or 904, then look at your tranny in the Ram. I
still
think they just copied the pics out of the old service manual!) It may
not
help your tranny shift harder but in theory the life could be extended.
Here
are a coupla reasons:
 
(1) If fluid starts to foam, you can loose pressure within the tranny,
when a
fluid pump is pumping fluid at a certain pressure, it is also spinning at
a
pretty constant RPM (at constant speed, and load). A foaming pressure
which
cause the pressure to drop when passing through the pump will cause the
pump
to spin faster to try and maintain the pressure. (kinda like trying to
suck
your drink through a straw when suddenly it develops a hole, kinda hard
aint
it???!!)
 
Anyway, this cuase the pump to work harder, and spin faster, hence less
life.
Even if the fluid does nothing, it wont hurt anything. Its been used for
years
as an additive, this is just a newer area.
 
(2) Clutch failure in a tranny is emminent, it will happen eventually
becuase
the clutchs slip to provide a nice smooth shift. The Hypoid Gear Additive
helps the clutchs to grip a little better instead of slip. Less slip in
this
case will help the tranny to live longer, and with no shift kit installed
it
probably wont even be noticable when shifting. If not, it wont hurt
anything,
hasnt in mine. Even if it does nothing, maybe it might add a little piece
of
mind if nothing else.
And lastly, here is what he has to say about using Mopar 'new generation'
fluid in older trannies;
Again, most of the above info if my thoughts, experiences and opinions
with my
own tranny. If its wrong, so be it, I take NO RESPONSIBILITY WHAT SO EVER
if
you decide to add these fluids to your transmission. A transmission is a
precision piece of machinary and can easily be ruined by inproper care
and
maintence. (trust me, Mopar trannys HATE Dextron/Mercon tranny fluid!!
Just
ask the 727 behind my 600+ hp 440, it died in a year, not knowing that
Dextron
fluid sucks and my driving style probably didnt help!)
So, any thoughts on this? Harmful, possibly helpful? Seems to me the LS
additive does the opposite of what he thinks it does, but I may just be
thinking wrong.  Inquiring minds want to know!
Dennis

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