'97 Civic Shifting Roughness

Hello,
I have a '97 Civic that I bought recently. It has a 5 spd tranny. If I am
reeaally careful letting the clutch out, I can make it shift smoothly.
Shifting like I have any other car I've driven tends to be kind of rough and
jerky. It has 100K miles on it. After I bought it, I changed the manual
tranny fluid with the Honda fluid and noticed a big difference although it
is still sensitive. I think that this was the first time that it had been
changed. Would it be worth changing again to flush out the rest of the crap
that may be in it? Are there any adjustments I can make to the clutch?
Lastly, any other thoughts on why this is? Other than that and a vibration
that I think comes from a heat shield when cold, it is a great car.

Thanks,
Bob

 

I am taking a manual tranny course right now and can offer
some of the book and ASE test answers, backed up by what I
saw in lab.

Having to be real careful when letting up on the clutch
pedal in order to get smoother shifting strongly suggests to
me that your Civic needs a clutch job: New friction disc,
pressure plate, release bearing. Also possibly resurfacing
of the flywheel.

You can try checking the linkage bushings and pivot points
shown at the link below, and performing the gearshift cable
adjustments shown. Replace the bushings as needed, or apply
light oil. I would not be optimistic this is going to help.

http://media.honda.co.uk/car/owner/media/manuals/PreludeManual/62sf100/8-3.pdf

The engine mounts, if worn, can change the effective length
of the clutch or gearshift cables and so cause problems.

Other causes are internal to the tranny, but these tend to
be less likely than simply needing a clutch job.

For your reference: The Honda OEM MTF is also said by others
to give smoother shifting.

100k miles is a good lifetime for a clutch, though this may
vary a lot from one driver (and driving locale, etc.) to the
other.

My 91 Civic has 180k miles on it, original clutch.

I had a Nissan whose clutch gave up at 115k miles.

 

.... OTOH, the more I think about that MTF perhaps staying in
there for 100k miles, the more likely I think it is that the
tranny gears, for one, may have suffered some serious wear,
or there is a lot of gunk still in there.

A second (or third and fourth?) MTF change may help. If you
want to save money, you could flush it with ordinary SAE
10W-30 or 10W-40 motor oil. The owner's manual says this is
okay for short periods (I think it gave a time period, at
least; double check). Certainly for an effective flush,
where I recommend you drive for a very short period between
changes, it should be fine.

The most obvious symptom of needing a clutch job is
slipping: While upshifting, the driver lets the clutch pedal
out, whence the engine revs more than usual. This is because
the clutch disc is not being held firmly between flywheel
and pressure plate. Power is thus not being transferred
properly to the wheels, so the expected acceleration of the
car does not occur.

 

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Bleeding the brake fluid in the hydraulic system that moves the clutch
might make it work closer to the 'design'. It should have been done the
last time the brakes were bled, but nobody asks / nobody tells the
mechanic.

'Curly'

 

A factor often overlooked is engine health. If the injectors are dirty or
the ignition needs tune-up the clutch release can often be the first to
suffer. Try a bottle of injector cleaner (most people favor Techron, but I
have also had good results with the much cheaper Pyroil); can't hurt, might
help. If the ignition tune-up parts (cap, rotor, wires and plugs) are old,
replace them first. Except the plugs - which can be NGK - use only OEM parts
for that. Many of us have learned the hard way about that.

Mike

 

Thanks for the suggestions. I think I'll try flushing it a few times with
10w30 and then add the Honda MTF. I may go ahead and flush the clutch
(brake) fluid. I'm not sure if they did that when I bought the car or not.
I know they did flush the brake fluid; not sure about the clutch. Guess it
couldn't hurt and is a small amount anyway.

It doesn't slip at all so I'll hold my breath and save money on a new clutch
until the problem gets worse. It's not really that bad now; just annoying.

Bob

 

Clutch could be nearly worn out. When the linings are at the end of their
lives, the "marcel" is greatly reduced, making it difficult to smoothly
engage the clutch.

An experienced mechanic can tell how worn your clutch is by how much the
slave cylinder rod sticks out.

 

Michael, can you explain this? Do you mean the stuttering
(or whatever irregular gas/air flow/spark at the cylinders)
sort of fools the driver into thinking it's a shift problem?
E.g. As the gas pedal is pressed during up shifting, engine
RPM does not change the way it should, so the shifting is
not all that smooth?

 

I would guess uneven acceleration which would in turn amplify a failing
clutch symptom...

JT

 

Yes - the engine bogs down easily and becomes ragged. I think it may go into
a subtle "pilot induced oscillation" where the engine starts to rev and the
driver's foot lets out a bit more, only to put more load on the engine than
it can handle. I could be wrong about that. I've noticed it in my older
Volvo (1970) when the points needed attention and in an '84 300ZX when I ran
it on cheap gas too long. My son's '94 Acura also started doing that, and a
bottle of Techron improved it about 60-70 percent over the course of a week.

The first time I encountered it in the Volvo I assumed it was the clutch -
until the morning the engine wouldn't start. After filing the points the
clutch was magically smooth again, and the light came on over my head.
"Sayyy...." After that, whenever the clutch got touchy I would rework the
points and be stylin' again. OTOH, I had a work truck that wouldn't start
one morning (you'd think it wouldn't need a tune-up after 150K miles/9
years!) and it never got "grabby." Huh.

Anyway, in the spirit of "make everything right first, then troubleshoot" I
like to rule out tune-up issues.

Mike

 

for brevity snipped the usual good anecdotes; please look
back

I buy it. I also googled and this came up on at least one
least web site, too.
See http://www.knight-rider.org/mn-dsm/tips/Spark.html

JT, I concur.

It's a very good point, IMO. Plus, one is not throwing money
away by doing a tuneup, either.

I agree this is a proper troubleshooting approach.

 

Curly,
That did the trick. Much better now. Thanks!
Bob

 

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See, I can guess them even when it's not Psychic Wednesday !!!

I'm glad for you. A crappy clutch would be hard to live with.

'Curly'