mystery of corolla differential runs dry

Jack wrote:
> THere is the same rubber thing to be removed from my father's '97, not
> sure what that part is for but it is there. I tend to believe my
back. It made little or no difference in operation of the
> > car. So I don't think you have a problem but anything could happen!


My shop said that the differential is automatically changed when you
change the transmission fluid. Sounded weird, but is it true?

I have a 95 Corolla.

A 95 corolla can have either a four speed or three speed tranny. If it
is a three speed unit like my dad's the differential has to be drained
and filled seperately.

On Fri, 02 Sep 2005 05:56:39 -0700, Jack wrote:

> I never knew of the vent that you mentioned. And this make me think of
> another possibility. Recently there had been a small scale flooding
> where my father lives. He told me he once drove through water as high
> as the top of the bumper. Would it be that some water got past the vent
> and enter the differential, push out some oil to the transmission ( I
> think the tranny and the differential has a pathway where oil can
> exchange). When the unit get hot the water got evaporate through the
> vent, leaving very little oil in the differential.
>
> Is this possible ?


Quite. Remember, fluids are not compressable, so if water leaked through
any vent, it would raise the level of fluid and not leave much room if
pressure builds. But if the vent were closed enough to keep the pressure
in, I doubt it would let water in.

But you never know.

When I was working as a salesman at a used car dealer, we bought a bunch
of cars that had come from a flood in PA. Most of them just needed to be
drained, refilled, cleaned and dried. But every once in a while we would
get one where someone tried to start the engine without draining the
fluids and, BAM! Hydraulic lock, where the engine blows because it is
filled with liquid. The same thing that keeps your car from starting if
you put in too much oil.

Just yesterday I was flushing the bosses transmission (97 camery) and saw
the second plug. Pulled it to drain the entire transmission and noticed the
fluid wasn't as dark as the rest. Looked it up and discovered the final
drive section..
Now what if I assumed that it was part of the transmission and thought that
it was filled through the fill tube? Or an axle was removed and it dripped
out there and the tech didn't know it was a separate fluid area?

my 2 cents.




--
Stephen W. Hansen
ASE Certified Master Automobile Technician
ASE Undercar Specialist

http://www.troublecodes.net/



"Jack" > wrote in message
oups.com...
> My father's 97 corolla with the 3 speed transmission recently develop a
> whine. Drove it to my usual mechanic where he suggested to try change
> both the oil in the tranny and the differential to see if it helps.
> (this transaxle has a seperate differential drain plug). The tranny was
> drained first and the fluid looked and smelled okay. Then he open up
> the drain plug of the differential - I could not believe my eyes that
> only a few drops drained out, it was almost dry !
>
> My question to the group is : how can the differential run dry without
> my father noticing any leak ? I am very sure there is no stain on my
> father's drive way, where he park his car 99% of the time. Where would
> have the oil gone ? I was thinking of the drive axle oil seal but my
> mechanic said it looked okay.
>
> Last time the car had the transmission and differential oil change was
> about one year ago at the same shop. I am thinking if my mechanic
> forgot to fill the differential during the last change, how could the
> unit went one year a few thousand miles without blowing up ? Actually
> according to my dad the whine only developed in the last few days.
>
> Any suggestion about what could have caused the leak ?
>

Jack wrote:
> My father's 97 corolla with the 3 speed transmission recently develop a
> whine. Drove it to my usual mechanic where he suggested to try change
> both the oil in the tranny and the differential to see if it helps.
> (this transaxle has a seperate differential drain plug). The tranny was
> drained first and the fluid looked and smelled okay. Then he open up
> the drain plug of the differential - I could not believe my eyes that
> only a few drops drained out, it was almost dry !
>
> My question to the group is : how can the differential run dry without
> my father noticing any leak ? I am very sure there is no stain on my
> father's drive way, where he park his car 99% of the time. Where would
> have the oil gone ? I was thinking of the drive axle oil seal but my
> mechanic said it looked okay.
>
> Last time the car had the transmission and differential oil change was
> about one year ago at the same shop. I am thinking if my mechanic
> forgot to fill the differential during the last change, how could the
> unit went one year a few thousand miles without blowing up ? Actually
> according to my dad the whine only developed in the last few days.
>
> Any suggestion about what could have caused the leak ?

The typical answer is that the diff wasn't filled through it's separate
fill point, which is threaded into the flat, vertical, aluminum diff.
plate on your A131E transaxle. Having driven it for a year without
mass destruction of the differential section is improbable, but
possible.

A less likely scenario would be that the fluid leaked through the
internal case seals into the regular fluid reservoir. This would show
as a higher than normal level on the dipstick, unless there is *also* a
fluid leak present.

Don't think that 'mechanics' always remember to fill the separate diff
reservoir. I have seen plenty of Jiffylose jobs come in on a hook just
miles after a trans service with an dry diff full of metal shrapnel.

Jack wrote:
> THere is the same rubber thing to be removed from my father's '97, not
> sure what that part is for but it is there. I tend to believe my
> mechanic since he has been a very competent and knowledgable guy ever
> since I started using him six years back, but still everyone can make
> mistakes.... if it is not him it would be difficult to find a reason
> for this mysterious oil loss..

There is no rubber part related to draining your A131E transaxle. It
has a pan drain plug, a diff drain plug, a diff fill plug, and a
dipstick tube for filling the trans section. The pan gasket has rubber
in it, but I doubt that is what you are refering to.

Toyota MDT in MO

"no rubber part related to draining your A131E transaxle."

It's weird because I saw my mechanic remove a black rubber thing before
he could get to the differential fill plug.

Jack wrote:
> "no rubber part related to draining your A131E transaxle."
>
> It's weird because I saw my mechanic remove a black rubber thing before
> he could get to the differential fill plug.

That would be the frame vibration damper. Not a part of the transaxle,
but it gets in the way of the diff fill plug if you don't have the
exact combo of tools to reach in there. It's absence does make plug
removal easier.

Maybe the mechanic removed that plug and no fluid ran out, so he
thought the diff was empty, or the translation of what he actually said
got lost somehow. On a properly filled A131E, fluid will be right at
the level of that plug hole when cold. It may run out a bit which is
OK, but if it is significantly lower than the hole when checked with
your pinkie, then the diff is low.

If you remove the drain plug on the *bottom* of the diff, aprox 1.4 Qts
of ATF will drain from a properly filled unit.

Toyota MDT in MO

"Maybe the mechanic removed that plug and no fluid ran out, so he
thought the diff was empty,"

Thanks for your response. I remember my mechanic drained the
transmission first (I stood under the car with him), then the
differential. The tranny drained okay but nothing but a few drops came
out of the diff.
I couldn't believe my eyes when I saw it.

Does a 95 Corolla with overdrive have a separate transaxle oil thing
than the transmission fluid?

I had them change the fluid and they said it was all one big thing, so
it wasn't really possible to change the axle fluid or whatever it is.