Transmission Lubrication

How do I lube a 4 speed manual transmission, in the 88-91 Civic Hatch? I
know I have to use gear lube, but where do I put it?!?

 

If you look at the right-side face of the transmission housing (where
the right CV shaft comes out the differential), there is an oil filler
plug above it (on the side face). The transmission drain plug is at the
bottom (side) of that side-plate.
Replacement capacity = 1.8 L (1.9 U.S. quarts)
Torque settings: Oil filler plug = 45 N.m. (33 lb-ft)
Oil drain plug = 40 N.m. (29 lb-ft)

Use Genuine Honda Manual Transmission oil, NOT gear lube. The manual
will say to use 10W-30 engine oil, but that was 15 years ago. From what
I have heard, the oil chemistries have changed, so need to put the
Honda stuff now (dealer service departments stock it....about $3 per
quart). If you have problems locating the filler and drain plugs please
drop a line, I will scan the diagram off the service manual and e-mail
it over.

 

you sure its gear lube? i thought that generation used 10w40.

 

You have to put the car on stands and get underneath. There are two plugs
in the side of the tranny case pointing at the right front wheel. The upper
one is a fill, the lower one a drain.
http://www.tegger.com/hondafaq/misc/92-95_civic_mt_oil_change.pdf

The above PDF is from the '92-'95 Civic, but the plug locations are the
same as yours. The drain plug takes the square drive of a ratchet. Scrape
out the dirt before inserting the ratchet to make sure it goes in far
enough not to strip as you try to crack the drain loose. If the plugs have
not been removed in a long time, you may have great difficulty breaking
them loose.

To fill, you need to have the car LEVEL, and you'll need a pump to attach
to your lube bottle (a lot like a hand-soap bottle pump). The pump needs to
have a clear vinyl hose that goes into the fill hole. Fill until it
dribbles out.
The pump is available at any auto supply store. The vinyl hose can come frm
Home Depot if your pump didn't come with one.


And use Honda MTL, not "gear lube" or the 10W-30 specifed in the workshop
manual.

 

A 1.5 foot breaker bar should be sufficient, though as
always, be careful. Brace yourself so you don't get hurt,
etc.

Gravity feed works fine for 88-91 Civics; no pump is
necessary.

Buy the clear tubing at Lowe's or Home Depot for a few
bucks, tops, probably. Three feet should be plenty.

Elaboration: Reports are that superior shifting occurs with
the Honda MT fluid. More importantly, there are many claims
on Usenet that 10W-30 and -40 have changed since about 1991
such that their chemistry is deleterious to the
transmission. I don't buy that--yet. I have always used my
91 Civic's manual-specified 10W-30 or 10W-40. No problems
after 173k miles. Anyone saying there will be problems down
the road is speculating based on rumor innuendo. (Unless
someone finally has coughed up a reputable citation on the
subject.)

If Honda thought 10W-30 or -40 today is dangerous to the
transmission, I think they would have said something.

www.autozone.com has a free online repair guide /specific/
to the 88-91 Civic that covers manual transmission fluid
changes. With drawings and photos.

 

And make certain the ratchet square is well seated. You don't want to round
off the square in the bolt.

Gravity works fine for my car too, and I used that method for years. But
I've since found it's easier using the inexpensive hand-pump.

The anti-wear additives (ZDDP, for example) that used to be present in
motor oils have been greatly reduced or eliminated in the interests of
protecting the catalytic converter. Transmissions have no cat issues, so
Honda MTF has loads of anti-wear additives (hence its distinctive odor).

They have.

An example from the '02 RS-X manual (pg 13-4):
"Always use Honda Manual Transmission Fluid (MTF). Using motor oil can
cause stiffer shifting because it does not contain the correct additives."

 

Just checked the '96-'00 Civic Helm manual. It contains the same warning,
word for word.

 

Sort of. But I don't discount the substance of what you
cited.

correct additives."

ISTM a manual transmission is pretty much a manual
transmission, so I agree that what's written in the 2002
Honda manual you cite above should apply to any year's
transmission, including my 1991 Civic's. In the future, I
will take note of it in posts, as it is helpful.

OTOH, I remain hesitant to translate this to a prediction of
disaster if one uses 10W-30 or -40. I can see that "stiffer
shifting" implies more wear, but ISTM it might be
negligible. Especially since the statement is qualified with
"can cause" vs. "will cause." To read this like a lawyer
blah blah...

So I'm not panicked on this point. My intent, stated in the
recent past, is to switch my 91 Civic to Honda MTF when the
next tranny oil change is required, see if the shifting is
superior, and draw more conclusions then.

 

Go back another decade to the generation the OP has and check again. We had
an '81 and an '87 and the recommended manual trans fluid was 10w-30 motor
oil. There was also a caveat to not use synthetic because the synchros
wouldn't work correctly with it.

 

Yes, and my '91 Integra's shop manual also specifies 10W-30.

But the point is that the motor oils in use now are not the same as those
available in 1991. Honda's metallurgy for synchros is unlikely to have
changed more than motor oil formulation.

It appears that the changeover to the MTF specification coincides with the
planning and implementation of much stricter OBD-II emission controls,
which would have been the primary driver behind zinc and sulfur reductions
in motor oils.

Synthetic motor oils have greater film strength than mineral oils and are
meant to reduce friction as much as possible. Synchros require friction to
function. If the synchros cannot work correctly with the oil film that lies
between their surfaces, they cannot correctly apply the friction that makes
them work. Zinc and sulfur are sort of "sacrificial anodes", taking the
brunt of the friction before the underlying synchro metal does, should the
oil film break, which it will under heavy use. This is the reason Honda's
MTF has the additives it does.

Honda MTF is the preferable oil for any Honda manual transmission that
originally specified 10W-30.

 

I plant o use MTF next as well but....

my '93 civic honda sevice manual says 10w30 or 10w40 with a service grade
of SF or SG

would not the sevice grade SF / SG matching cover the concerns of oil
formulation.

robb

 

Lubrication wise, yes. But those ratings relate to the oil being used as
motor oil, not transmission oil. The problem with synthetic (i.e. Mobil 1)
was that it was (is) too slippery for the synchros to work correctly. They
depend on a little friction to get them moving.

 

Yeah. It was printed before the changes to oil configuration, as I said a
few messages ago.

SF & SG are obsolete. Good luck finding that stuff these days. All you'll
find now is SL and SM.

 

well that is the issue then, *if* you could find SF/SG then you'd be ok but
10w30 spec is useless by itself ... where most people seem to be betting on
10w30 == 10w30 not

robb

 

if you can find oil that old. the concerns these days are all the
friction reducers put into current oil grades that MIGHT cause the
syncros to not work right.

too much slipperiness can be a bad thing.