transmission fluid diagnosis (yes I read previous postings)

[Gunther Schadow]

Hi Guys,

I just joined this newsgroup, need some support group as I'm a
car cheapie and so I'm in for trouble :-). Say, is this *the*
place for car tinkerers to be or is there also a mailing list?
It looks pretty neat here.

O.K. here's my problem. Have a Chevy Caprice 1993 5.7 L, LTZ,
120000 (not actual???) miles. Bought it for $1800 on ePay.
Turned out problems with the tranny. When I bought it things
looked fine. At 1000 miles (maximal) later, the fluid lost its
red color, was all yellowish brown and smelly.

So, I thought may be I didn't look right at first
and started replacing. The messiest thing I ever did. Pan down
and up refill run engine stop, pan down and up refill run engine
stop ... and so forth. Thus I replaced some 12 to 15 gallons
until at the end it looked fresh and new and it was shifting
much nicer (I want it shift below 2000 RPM.)

Small detail: I refilled perhaps a slight bit above the "full"
mark on the stick. Let's say just a quarter inch or so.

Now, just about 3000 miles later I'm beginning to see problems
again. Shifts only above 2000 RPM, doens't want to shift all the
way up. I'm learning to manipulate with the trottle to make it
shift when I want... Now as of late, when its cold, it doesn't
shift up 1st gear at all until it's warmed up good.

What's the diagnose? I'm thinking of some things but would like
to know how I can tell for sure:

1) overheating due to stuck cooling circuit
2) overheating due to internal wear (slipping? I didn't notice?)
3) was that minor overfill that big of a deal?
4) do I have an engine coolant leak into the tranny fluid

A quick fix would apparently be to flush the fluid again. I
do not urge to do it the messy way again, so either I'll do
it with a hose and sucking off through the dip-stick shaft
or will go to a flush shop, if that's available for, say,
about $50 for a flush. What's a good place in Indianapolis
to do that?

I really want to rule out issues with the internal coolant
leak before I spend hundreds of $ on an overhaul that does
the transmission fine but doesn't solve the cause, if that's
the problem. What costs am I looking at for the following
three scenarios:

1) go to the flusher at every oil change interval
2) have tranny overhauled
3) require new tranny

thanks for your advice,
-Gunther

[Dean Dardwin]

Gunther,

Take it to any radiator shop. They will pressure test the cooling
system. If there is a leak in the tranny cooler inside the radiator, you
have two choices. You can get the cooler replaced or plug the ends and
install a new aftermarket tranny cooler in front of the radiator.

Then, buy a tranny pan with a drain plug in it or add a plug to yours.
Change the fluid 4-5 times over a week. Then pull the pan and change the
filter. I'd strongly suggest Mobil 1 ATF. I've saved a few this way but
it all depends on how much internal damage has been done. Some times you
get lucky, some times you don't.

Dean

[bka...@snotmail.com]

In article <3C2085B1...@aurora.regenstrief.org>, Gunther Schadow
<gun...@aurora.regenstrief.org> wrote:

Try changing the filter! The old one is probably somewhat clogged and
won't pass the cold, thicker ATF. After the fluid warms, you get
sufficient flow through it. Meanwhile, you are slipping the clutches/bands
and burning all that nice new fluid you put in it!

--
To Email me, change snot to hot

[Family]

Paul wrote:

Two things I would do.

1. Put a drain plug on the tranny pan 10 bucks.

2. Disconnect tranny lines from radiator.
Install a transmission cooler in front of the
radiator. This will definitely solve the problem
of coolant ever mixing with the transmission
fluid

[Geoff Welsh]

And on finding a cooler....I think they came stock with the Police package.
There's LOTS of wrecked cop cars in the world. The trick is finding one
that's not still "evidence".

[Gunther Schadow]

Thanks to those who responded on my earlier posting. I

have some new evidence. I'm so hesitant to do something
because I didn't have the time and I'm afraid to have
a big problem.

>>O.K. here's my problem. Have a Chevy Caprice 1993 5.7 L, LTZ,
>>120000 (not actual???) miles. Bought it for $1800 on ePay.
>>Turned out problems with the tranny. When I bought it things
>>looked fine. At 1000 miles (maximal) later, the fluid lost its
>>red color, was all yellowish brown and smelly.
>>
>>So, I thought may be I didn't look right at first

>>and started replacing. Washed with a dozen of gallons ATF

>>until at the end it looked fresh and new and it was shifting

>>much nicer.

>>Small detail: I refilled perhaps a slight bit above the "full"
>>mark on the stick. Let's say just a quarter inch or so.

>>Now, just about 3000 miles later I'm beginning to see problems

>>again. Worse problems. Initially it began shifting at higher

>>RPMs (~2500).

bka...@snotmail.com suggested:

> Try changing the filter! The old one is probably somewhat clogged and
> won't pass the cold, thicker ATF. After the fluid warms, you get
> sufficient flow through it. Meanwhile, you are slipping the clutches/bands
> and burning all that nice new fluid you put in it!

The new pieces in the puzzle are:

First, I did replace the filter back then. And it ran fine
for several months!

Second, the fluid has not become so bad as I said earlier.
It's still pretty good red.

Third, I did make the mistake leaving the old o-ring in
before sticking in the new filter. But it fit very well
then (so I dind't notice) and remember it drove fine for
over 2000 miles or so.

Lastly, I noticed something else that I didn't think was
related: the speedometer would show 0 (zero) until the
engine was warm (a few miles driving). I just learned that
the speedometer is driven from the transmission, right?

More exactly, the speedometer will show something a for
a few yards when stating to drive cold. Then at the first
stop or when speeding up too fast the speedometer will
"break down" to zero.

Interestingly the behavior changes on a half-daily basis.
For quite a while the speedometer was showing zero a few
miles, before any transmission worries even started.
Then the transmission got worse, not shifting above 1st
gear for a 1 or 2 miles or so. Then it was fine again
(well just about). Then the other day stuck in 1st
gear for 1 mile. Yesterday morning, everything was just
fine again, the speedometer was fine too.
Last night, however, things got real worse with it not
going above 1st gear for 5 miles or so. This morning
the story was the same. So, I guess things are heading
south.

Does it make any sense to try filter change and fluid
change without a major transmission overhaul? Given that
winter has finally struck and that I am still fed up
from this mess (and the mechanical difficulties) from my
last fluid change, I'd bring it to a lube shop. But
they will probably believe I'm nuts because I want a
fluid and filter change on a half-dead transmission,
right?

regards

-Gunther

[Loren Knighton]

>Lastly, I noticed something else that I didn't think was
>related: the speedometer would show 0 (zero) until the
>engine was warm (a few miles driving). I just learned that
>the speedometer is driven from the transmission, right?
>
>More exactly, the speedometer will show something a for
>a few yards when stating to drive cold. Then at the first
>stop or when speeding up too fast the speedometer will
>"break down" to zero.

>For quite a while the speedometer was showing zero a few

>miles, before any transmission worries even started.
>Then the transmission got worse, not shifting above 1st
>gear for a 1 or 2 miles or so. Then it was fine again
>(well just about). Then the other day stuck in 1st
>gear for 1 mile. Yesterday morning, everything was just
>fine again, the speedometer was fine too.
>Last night, however, things got real worse with it not
>going above 1st gear for 5 miles or so. This morning
>the story was the same. So, I guess things are heading
>south.
>
>Does it make any sense to try filter change and fluid
>change without a major transmission overhaul? Given that
>winter has finally struck and that I am still fed up
>from this mess (and the mechanical difficulties) from my
>last fluid change, I'd bring it to a lube shop. But
>they will probably believe I'm nuts because I want a
>fluid and filter change on a half-dead transmission,
>right?
>
>
>regards
>
>-Gunther

Gunther:

On the tailshaft housing of that transmission is the VSS (vehicle speed sensor)
not only does it send a signal to the computer which interprets the speed of
the vehicle-but also the computer commands shifts according to vehicle speed.
My guess based on the speedometer doing nutty things is that the VSS is crapped
out. Resistance should be 1260-1540 ohms @ 68 degrees F. Output voltage will
vary with speed from a minimum of 0.5 volts AC at 100 RPM to more than 100
volts AC at 8000 RPM. There is a good chance the trans is fine-but it needs
some electronic troubleshooting. The above is based on you having the 4L60-E
model transmission in that 1993 Caprice. If it is then you will have a round
electrical connector going into the transmission case located on the passenger
side of the case towards the back of it.
Good luck to you.

Respectifully submitted,

Loren Knighton
Woodland, CA.
IATN, TRNI
Under the hood since 1964