Post by Ray OPost by H ZI spoke w/ a Lexus Master Technician today who said that my problem is
that the sharp decline of the mountain rushed all of the trans fluid
to one side of the car and that's why I was having problems only in
that situation. An answer like that actually makes sense to me and
that's the best he can do w/o looking at the car.
His diagnosis was that I didn't have enough fluid. However, according
to the dipstick I am at full. So for now I may just keep the car
locally and avoid long mountainous road trips for awhile.
Does the master technician's answer sound possible?
The answer is possible if the ATF level was low, however, it is easy to
confirm whether or not the answer is correct. Under the same exact
conditions, the vehicle will exhibit the same behavior.
To answer your earlier question, it doesn't sound like the incorrect ATF was
used because the vehicle would exhibit problems under a wider variety or
driving conditions. I asked the question to see whether the ATF had
deteriorated, which it doesn't sound like. ATF is much thinner than motor
oil, especially when hot.
In your original post, you said that the transmission didn't respond when
you gave it gas, but did the engine respond?
Your transmission will downshift under certain conditions, and 2,000 RPM
while going down a fairly steep road doesn't sound excessive. If the
transmission upshifted when the grade leveled off and the ATF is translucent
and pink (and the correct ATF is used), I wouldn't worry.
--
Ray O
(correct punctuation to reply)
Well when I checked the condition of the fluid via dipstick it seemed
ok but on a closer inspection I may have solved my own question.
Please visit the following page.
http://www.handogg.com/atf.jpg
The first glass is fresh ATF fluid w/ a cranberry juice type color.
The second is ATF as it came out of the car. It had more of a grape
juice color. At the same time fresh motor oil looks much different
than motor oil that's been used even just a couple of times. From
what I remember fresh motor oil is a honey color but after just a
little bit of use it turns black right away.
Ray, can you confirm that the condition of the ATF is so bad that it
is likely causing the problem or could it be something else? I feel
like I should be worrying because this is a new situation that has
never happened before.
Thanks much..
********
In your previous post, you mentioned that when you hit the gas, the
tachometer would indicate an increase in engine RPM but that the car would
"stall" a bit.
The computer that controls the transmission looks at inputs from several
sensors to determine which gear the transmission should be in, and whether
or not the torque converter should be locked or unlocked. Among the inputs
are vehicle speed, throttle position and whether or not the brakes are
applied, and from the various inputs, the computer infers whether the driver
is trying to accelerate, cruise, coast, or whether the vehicle is going down
a long incline.
Unfortunately, I cannot conform that the condition of the ATF in the photo
is so bad that it is likely causing the problem, but if there is enough
contaminants that the fluid is opaque, it is a good idea to change it. Does
the used ATF have a burnt toast smell or smell significantly different from
the fresh ATF? If so, the ATF needs replacement.
Automatic transmissions have numerous internal clutch packs, and the
friction surfaces wear just like the friction surface on brakes or on a
manual transmission clutch. ATF becomes dark because it becomes
contaminated with the worn friction material, kind of like how a car's
wheels become dirty from brake dust material. Eventually, the contaminants
in the ATF will affect the movement of spool valves, solenoids, and how the
friction materials act enough so that the transmission doesn't shift or hold
gears properly.
Judging from the color of the used ATF, I would change it but do not have
the transmission flushed because flushing a high mileage transmission tends
to cause problems.
--
Ray O
(correct punctuation to reply)
