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| Automatic transmissions are complicated, but some simple diagnosis can go a long way. |
Automatic Transmission
Diagnose Automatic Transmission Problems
By Matthew Wright
There are a few words in the
language of auto repair that make car owners want to crawl back into bed, and
"transmission" is at the top of the list.
Unfortunately, most repair
shops know this, and will take advantage of the situation by reaching deep
into your pocket.
Before you hand over your
keys and a blank check, brush up on the simple end of automatic transmissions.
If something is seriously
wrong, at least you'll be armed with enough knowledge to avoid being
overcharged, over-repaired or straight ripped off.
Your transmission is a
remarkable contraption.
Somehow, it can shift your
car from gear to gear, knowing how fast you need to go and how quickly you need
to get there.
What goes on inside is a
mystery to most.
Unless your thirst for
automotive knowledge borders on compulsive, you can leave it a mystery.
The basics will be enough to
have an intelligent (which translates to "not about to be ripped
off") conversation with your mechanic.
Basic Parts of a Transmission
While
there are many, many little parts inside, your transmission is essentially made
up of a few key systems.
·
Bell Housing: This
is the cone shaped metal case that you can see when you peek underneath your
car. If you have a front-wheel-drive car, it's stuck on the side of the engine
under the hood. If your car is rear-wheel-drive, the transmission will be
mounted underneath the car behind the engine.
·
Gears: Even
though you're not shifting them, an automatic transmission has gears. They are
broken into main gears and planetary gears. You need all of these to be able to
drive.
·
Fluid: Transmission
fluid is very important
to an automatic transmission. All of the magic happens in the fluid. Most cars
come with red transmission fluid, good to know if you are looking for a leak.
·
Filter: All
of that fluid has to be clean for your car to shift gears at the right time. To
keep things fresh, your transmission has a filter to catch any gunk.
Now that you know a little
about what's happening in there, you can try to figure out why your
transmission is acting up, or at least understand what your mechanic is talking
about while he tries to make your bill into his new fishing boat.
Transmission problems fall into
two very similar categories:
·
Won't go.
·
Won't go smoothly.
These two groups of problems
are caused by the same faults in your transmission, so whichever your car is
doing, the following applies.
Is your fluid level correct?
It's
important to check your transmission fluid at least twice a year.
Not only can a low fluid
level cause your car to shift poorly, it can eventually lead to transmission
damage, and a costly repair.
If
your car seems to be losing fluid on a regular basis, you may have a leak.
Is your transmission leaking?
Checking
for leaks isn't as trying as it may seem.
The transmission is a closed
system, so there are only a few places that can spring a leak (first
check you didn't pour transmission fluid incorrectly).
Unless it's been changed to a
non-dyed fluid, your car will have red transmission fluid.
Here are a few places to
check for leaks:
·
At the filler tube base.
·
At the drain hole underneath the transmission.
·
Between the transmission and the engine.
·
At the selector shaft - the rod that connects your gear shift to
the transmission.
·
Speed sensor mounting point. This will either be your cable
screwing into the transmission housing or an electronic sensor bolted to the
housing.
·
The radiator. If your car has a transmission cooler, it's possible
that a leak will cause transmission fluid to leak into the radiator fluid.
They don't mix well, so you'll see it floating around in there.
Is your filter clogged?
Your
transmission's filter is vital to its performance.
If you haven't replaced your
filter in a while (or ever for a lot of us), be sure to do this before you start
talking about rebuilds or replacements.
Most transmission problems
can't be fixed by the average do-it-yourselfer.
There are just too many
specialized tools and pieces of equipment you'll need, and buying this
expensive gear just to screw up your first three tries at fixing the thing just
doesn't make too much sense.
Now that you're in front of
the firing squad, it's time to drop some knowledge on your fix-it guy. Tell him
what the car's doing.
Then
tell him what you found out when you inspected the transmission.
If
there's a leak, let him know where and how much is leaking.
Time for a Rebuild?
When your transmission gets
tired enough, you'll have to have it rebuilt. It's true.
For some makes and models of
car, it's true a little too often, but that's neither here nor there.
The important thing is
checking any other possible causes to your problem before you take the
transmission apart, which is very expensive.
If you haven't replaced your
filter yet, do it! This
fixes a nice percentage of transmission problems.
If your filter is good, and
nothing simple is out of adjustment, be prepared to drop some serious dough on
the rebuild.
The good news is that most
shops warrantee a transmission rebuild for a nice amount of time.
A small consolation as your
handing over the credit card, but at least you know that it will get fixed
and stay fixed.
You may
not be able to save big money by doing your own transmission rebuild, but
keeping up with your regular maintenance will keep you out of the shop as much
as possible.
Matthew Wright has been trained in both journalism and auto repair, with
extensive experience in both fields. He attended Georgia State University's
well known school of journalism, where he studied news writing. Prior to this
he worked for years in the automotive industry, running a repair facility in
Atlanta before moving to the great state of New York.
Experience
Matthew has experience in both journalism and
auto repair. He has worked in the automotive industry since 1989, specializing
in European auto repair and rebuilding. After almost a decade in the business,
he began working as a reporter in 1996, and has held positions as a newspaper
staff writer and magazine editor. After some years in journalism, he returned
to the automotive world, opening an exclusive repair and restoration facility
for vintage European makes.
Education
Matthew attended Georgia State University where
he studied print journalism and held the position of news editor at the
University's weekly newspaper, but the real education came from years of
maintaining, troubleshooting and repairing both my own cars and those for our
first repair facility, Wright Brothers Automotive. There is no substitute for
experience, and Matthew's experience goes back to 1989.
Matthew Wright
Doing your own auto repair, troubleshooting and
maintenance can be very rewarding! Not only will you save money by avoiding
some trips to the repair shop, the more you fix yourself the better you know
your car, and that makes sense on all fronts. With a little help, you can be
greasy and accomplished in no time at all. And for those times that a trip to
the mechanic is unavoidable, you'll know when you're being treated fairly and
when somebody might be trying to rip you off. Throw a little mechanic-speak
back at those guys and watch their tune change before your eyes. Now get out
there and dirty up!
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