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Transmission Leaks and
Operational Problems Question This
category contains featured questions as
examples. They relate to most vehicles.

Question:
1984 Nissan 300 ZX 3 litre V6 mileage:
112,000 km. My car is a 1984 Nissan 300 ZX with a three speed automatic with an
electronic overdrive for fourth gear.
When I switch the overdrive on, it stays in
third gear even when the car is warmed up.
The switch and overdrive solenoid are
working but I have been to several auto
electricians and they cannot seem to find
the fault. Could you please give me a
few suggestions on how to fix my problem?
Thank you.
Answer: The overdrive circuit is
controlled by the engine temperature sensor
to prevent it from going into overdrive when
the engine is cold. If the sensor is
faulty, it will not allow your transmission
to shift into overdrive. Also, check
the thermostat, if it is stuck open, it will
not allow the engine to come up to normal
temperature and the transmission will not
shift into overdrive.
Question:
1980 GMC Pickup Full Size Bed V8 mileage:
over 80K. When accelerating, the
automatic transmission will not shift into
the next higher gear unless I take my foot
off the gas a bit. In addition, the
engine must be racing before I can let off
the gas to get it to shift up.
Downshifts fine. What do you
think is causing the problem?
Thanks in advance.
Answer:
Check the vacuum modulator. It may
need replacing. Also, check the vacuum
hose to the modulator for leaks or lose
connections.
Question:
1984 Ford Bronco 2 4wd 2.8
mileage: 198,000. Reverse went out
but the other gears work fine. I was
told it was either the rear band or a servo.
My question is if it is a servo where is
that located and how can I tell?
Answer:
Sounds like you are ready for a
transmission overhaul. The reverse
band and servo are inside the transmission.
In order to tell if your problem is the
servo, you need a transmission specialist to
run a diagnostic.
Question:
1978 Chevrolet 350 mileage: 40,789. I
have a 1978 Malibu with a 350, how do I fit
a turbo 400 trans with a Ford 9 in rear end
behind it?
Answer:
The turbo 400 transmission should bolt
right in. The rear cross member may
have to be changed. A Ford 9 inch is a
big big project. A Chevrolet 12 bolt
would be a lot easier.
Question:
1992 olds cutlass 3.1_mileage: 154,000.
Hi guys, my wife's beater is surging
(lunging) at idle and when coming to a stop.
She related to me that it tried to take off
while stopped at a traffic signal (and of
course I thought "yea, right"). After taking
it for a spin, it sometimes thinks its in
third gear and stalls when coming to a stop
after an extended ride (25 mi.). This
is an intermittent condition. I had a
friend put it on the computer and there were
no trouble codes. He said it might be
a transmission sensor.
Answer: Your car has a
lock-up torque converter in the
transmission. It locks-up only in high
gear. It is supposed to disengage at
lower speeds. Yours is not
disengaging. There is probably a valve
in the transmission “hanging up”.
Having the transmission serviced with new
fluid may help the problem. The cost
is approximately $75.00 (Southern California
Prices). Next step, the valve body
will have to be removed and cleaned.
The cost is approximately $200.00
Question:
1980 Jeep cj-7 151
mileage: 198,640. I have an opportunity to
buy a 258 in-line 6 cyl for the same year
jeep (80). I currently have a 4 cyl 151. Is
there a problem with using the 151 engines 4
speed transmission? It was rebuilt and I
would like to use it.
Answer: Your transmission will not
work with a 6 cylinder engine, sorry.
Question: 1991 Ford Explorer
XLT 4.0 mileage: 144,000. Auto Transmission
slow to shift until warmed up. Hard driving
helps in shifting. After warm up, sometimes
easing up on the gas assists the slow
shifting. Changed filter and leaking
modulator valve 15k ago.
Answer: Try a different vacuum
modulator. The spring inside may be
incorrect for your car. If that does not fix
your problem, hang on to your wallet because
it is overhaul time.
Question: 1996 Jeep Grand
Cherokee Limit V8 mileage: 53,887. I recently
changed the automatic transmission filter,
gasket & fluid. The fluid that I used was
the Dextron 2. Now when I check the fluid,
the fluid has several air type bubbles. What
could be causing the bubbles and what needs
to be done to correct the problem? If I
check the fluid when the engine isn't
running there isn't any.
Answer: Your transmission may be
low on fluid. The bubbles may be the result
of air and fluid being sucked up into the
filter and pump. Check the fluid level first
thing in the morning after the bubbles have
settled down over night. Our guess is you
will find it low.
Question:
1966 Ford LTD 390 mileage: 60,000. I want to
replace the seals in my (automatic C6)
transmission, but I'm a beginning mechanic
and don't know how to go about it. I'm
looking for step by step instructions or
some kind of a repair manual, like Haynes or
Chilton's. My local parts place says they
can't order manuals back to 1966. Any idea
on where I can find information, or can you
give me the ABC's?
Answer: Removing and
reassembling an automatic transmission is a
big job for a beginning mechanic. You may be
able to find old repair manuals at your
local library. Also, try the
2Carpros Bookstore.
Question: 1991 Pontiac
Grand AM 2.5L mileage: 93,000. My '91 Grand
Am has a 3 speed automatic transmission with
overdrive. The overdrive kicks in above 45
or 50 mph automatically. When traveling in
overdrive for a long period (1/2 hour or
greater), the transmission will not shift
out of overdrive when slowing down or coming
to a stop and the car stalls. Upon
restarting the car, (in neutral or park) the
transmission is still in overdrive. In order
to get the car out of overdrive, I have to
rev the engine and drop it into drive (not
good). Do you have any idea what might be
causing this?
Answer:
Your car has a lock-up torque
converter in the transmission. It locks-up
only in high gear. It is supposed to
disengage at lower speeds. Yours is not
disengaging. There is probably a valve in
the transmission "hanging up". Having the
transmission serviced with new fluid may
help the problem. The cost is approximately
$75.00 (Southern California Prices). Next
step, the valve body will have to be removed
and cleaned. The cost is approximately
$200.00.
Question: 1981
Mercedes Benz 300SD mileage: 220,000. Want
to change transmission filter and pan
gasket. Because of mileage and not sure when
and if prior owner changed fluid, I am
afraid to have fluid replaced. Present fluid
clear and unburned. Should I chance or will
someone just change filter and gasket.
Second question, vacuum motor in trunk that
runs door locks and gas cap cover, quits
after about two weeks. If I pull out,
disconnect, and then connect three-prong
electrical connector, it works for another
two weeks. However, I believe that if I
disconnect the vacuum line to the motor, it
works for unlimited period.
Answer: If in doubt,
change the transmission filter and gasket
and at the same time replace the fluid in
the pan. With the transmission pan down,
inspect for metallic particles. A slight
amount is normal. About your vacuum motor
problem, a cracked and leaking vacuum hose
probably causes this. Locating and repairing
the hoses should fix the problem.
Question: Volkswagen
Quantum, 90,000 miles. I want to have my
transmission removed and replace instead of
having someone rebuild my old transmission
which is a automatic. I decided to use
another transmission from another Volkswagen
Quantum car that came with a warranty.
Approximately, how much should this cost? It
seems to me this would be a very simple job
because all it takes is unbolting and
removing the transmission, and inserting and
aligning the new transmission and re-bolting
it in. In addition, what are some other
things besides the transmission fluid and
filter they need to check or change when
replacing the transmission in a car?
Answer: Before having your
transmission replaced with one from another
Volkswagen, you should be aware that not all
transmissions are interchangeable. Although
they may appear the same, the manufactures
are constantly updating from year to year
and even mid-year. Your car may not be
compatible with another transmission.
Replacing the transmission is not a simple
job. Your Volkswagen Quantum is not a
"mechanic friendly" car. The labor cost for
removing and repairing your transmission
should be approximately $250.00. (Southern
California Pricing).
Question: I have a
1993 Aerostar with an A4LD transmission.
Recently in the morning after reversing the
car out of our driveway and slipping into
drive the transmission will not engage for a
few seconds. Upon engagement, it drives fine
all day long. Is this a band adjustment, or
a symptom of worse trouble on the way? If
this is a band adjustment, what is the band
adjustment procedure and specifications I
should use? Thanks in advance for our help.
P.S. It has been a few years since I turned
wrenches at repair shop!
Answer: A low
fluid level in the transmission may cause
the problem you describe. Check for external
leaks (oil on garage floor). Also, check the
vacuum modulator for a blown diaphragm
(fluid in the vacuum line at the
transmission). Another cause could be the
torque converter draining back into the
transmission overnight. If the converter is
draining back, the "fix" is very involved.
We do not think a transmission adjustment
will help.
Question:
I own a 1992 totally stock Toyota
4X4 V6 Truck with approx. 117,000 miles. At
about 100,000 miles, I had the original
clutch replaced. The clutch was working
fine, but because of the mileage, I felt it
would need replacing soon. Since the truck
would be spending some quality time at the
Toyota dealership for the infamous head
gasket problem, I felt this was as good a
time as any. The Toyota dealer replaced the
clutch, pressure plate, bearing, and turned
the flywheel. The new clutch grabbed when
starting off in first and especially in
reverse. It feels like the clutch is
chattering. I returned the truck to the
dealer with the above complaints. They claim
they replaced the clutch once again, but it
did not cure the problem. At this point,
they thought the recently turned flywheel
needed replacing, naturally at my expense.
After all this the truck still has the same
problem, but less severe. If driven
aggressively, the clutch works smoothly. The
problem is most evident if you just release
the clutch without applying the gas. My
question is, what other conditions could
cause this particular problem? Could the
strength of the new clutch accentuate worn
engine mounts? Would worn out bearings in
the rear end cause this, and if so, how can
you tell if the axle bearings are worn?
Answer: Your problem
could be caused by improper clutch linkage
adjustment. One adjustment is under the dash
on the clutch pedal to clutch master
cylinder. The other is on the clutch slave
cylinder on the engine. Yes, worn engine and
transmission mounts can also cause this. I
would be very surprised if the worn out
bearings in the rear end could cause the
problems you describe. You can check for
loose axle bearings by raising your truck
off the ground, lift each rear tire by hand,
and check for "play".
Question: My brother's
car blew a clutch today. It is a 1986 Mazda
626. About how much would a new clutch cost?
Answer: $300.00 to
$400.00 for labor and new parts: pressure
plate, clutch discs and release bearing.

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