This isn't something I'm going to attack myself, I'm more curious
about difficulty and price.
My 01 elantra stickshift is having trans issues. When downshifting
into 1st or 2nd gear I get serious grinding. It doesn't happen when
accelerating from a stop and/or shifting 1->2, or in any other gears.
People tell me my syncros are going, and while I understand the concept
of synchronizing the gear speed as they mesh, the actual mechanics of
it (or actually fixing it) are well beyond me.
It's going to go to a shop, but my question then is, how hard is this?
I have a bad feeling that the trans will have to be removed and some
serious internal work will be required, but I'm also a natural
pessimist. Any thoughts as to the difficulty?
I probably ought to get this done soon. Learning to float gears and
estimating proper rpms isn't coming to me quickly enough.
Unfortunately, your friends are correct. The 2 > 1 shift will almost
always grind if you're not at a dead stop, but if the 3 > 2 shift is
grinding, the synchronizers are probably worn.
Replacing the synchronizers requires a transmission rebuild, which will
likely cost $1000-$1500, most of which is labor.
If you're downshifting and engine braking, stop doing it. As you're
learning, brake pads are a lot cheaper than transmission rebuilds, so it
makes sense to use the brakes to stop the car, rather than wearing out
the transmission by engine braking.
That's up to you, as it's more of an inconvenience than a major problem.
It's not likely to cause a more serious failure, though it would
probably be a good idea to change the transmission oil in order to
remove as much of the wear particles as possible. I strongly suggest
using a good synthetic transmission oil like Redline MT-90. Regardless,
you MUST use a GL-4 oil ONLY, as Hyundai transmissions require it! DO
NOT let anyone put GL-5 or "universal" oil in your transmission, as it
will cause premature synchronizer wear.
Modifying your driving habits is an easy and inexpensive workaround for
the issue you're having and it will allow you to put off the rebuild
nearly indefinitely. If you continue driving in the same manner, you'll
quickly wear out rebuilt synchronizers too, making a rebuild largely a
waste of money.
Generally, all it takes is a well-timed blip of the throttle, which is
something you develop by feel. Still, I would recommend getting out of
the downshifting habit. If you're determined to keep doing it, learn to
I'm really surprised to see this Brian. Cars have been fully sychronized
for decades, so it really surprises me that there are not synchros between
1,2. I havent' owned a manual transmission for several years now, so I
don't doubt that there are trannys on the market that behave differently
than what I was last used to, but man - that's a step backwards.
For any particular car this may be dead nut truth, but as a principle of
manual transmissions, I'd have to disagree. I have always downshifted every
single manual tranny I ever owned, with no ill effects. No premature wear,
Ah - the good old days, huh? Remember when you had no choice - you had to
do this? Most modern manuals (qualified by the ones I've experienced) with
decent synchro's don't require a blip anymore, unless you're coming down
from way too high. In that case, it is questionable whether the downshift
should even be taking place at that speed/rpm. I have not double clutched a
manual in so long that I don't remember the last vehicle that I had to do it
in - other than a fire truck.
The difference in RPM is greater between the lower gears so the synchros
have to work a lot harder, however, my Sonata goes into first OK if you
are going less than 10 MPH or so. I always blip the throttle on down
shifts as well which helps.
Same here. This is the way standard shift is meant to be driven. It is
a good idea to blip the throttle on down shifts though to help
synchronize the speeds a little. I don't double-clutch my cars as I did
when I was driving OTR, but blipping the throttle helps and is easy.
Blipping the throttle isn't necessarily required, but it is very good
There are probably 1-2 synchros, but every car I've owned (I've never
owned an automatic) has had a tendency to grind during 2>1 shifts if the
car is moving. The Elantra definitely does. If you're moving at anything
more than a crawl, downshifting to first is unnecessary and pointless,
so I rarely do it.
Consider yourself lucky. Downshifting without RPM matching does wear the
synchros and engine braking wears the gears. Whether it's enough to
cause a problem over the typical life of a given transmission is
debatable. FWIW, I used to drive my cars hard, heel and toe downshifting
all the time and it never caused a problem (sadly, Hyundai pedal
placement is lousy for this). However, Hyundai transmissions are prone
to synchronizer wear (as I learned with my first one), so I don't
downshift/engine brake in the Elantra.
While that may be true, it doesn't mean it's good technique or that RPM
matching is not a MUCH better technique. It dramatically improves the
smoothness of downshifts while reducing wear on the clutch and
transmission. For that matter, if you match RPMs well, you don't even
need the clutch for upshifts OR downshifts. Again, this is not something
I do any longer, but I experimented with it years ago, so I know it's
possible. When you get it right, it's pretty amazing, when you don't it
True, but it depends on how aggressively you're driving. For example,
when braking hard into a low speed corner requires pretty dramatic
downshifting if you're planning on exiting said corner in a hurry.
I've never had a vehicle that required it, except for downshifting when
the synchros were worn.
My Sonata needs first below about 10 MPH. It is really gutless at low
RPM and doesn't pull away in second as my previous cars have done. It
seems to have almost no torque below 1500 RPM, unlike my pickup that
will pull literally down to idle.
Sure it causes some wear, but if you change your oil regularly this wear
is almost imperceptible. And the wear on the gears is on the other side
of the teeth which are seldom used so you are wearing a part that
otherwise sees no wear and in any event gets far less wear than the
drive side of the gear teeth.
If Hyundai's are prone to synchro wear, it is due to poor materials or
Those were pretty much my thoughts Matt. There is really no "consider
yourself lucky" about it - transmissions in general have no problems with
upshifts or downshifts. It causes no premature, or excess wear and tear.
Transmissions and engines are always out of synch in terms of rpm's whenever
a shift occurs - whether that is upshifting or downshifting. That's the
whole purpose and reason behind a synchro. I wondered about the Hyundai
transmissions based on what had been posted. If indeed, they do not suffer
shifting well, then that's a design issue. Brian's historical comments seem
to suggest this as well.
While gear wear may be small enough not to pose a problem over the life
of a transmission, that's not true of synchronizers, which do wear if a
transmission is shifted without matching rpms. The sloppier the shifts,
the more wear and tear.
I beg to differ, Mike. If you match RPMs, there is no significant
difference, which is why you can shift without using the clutch if you
match revs accurately. Granted, not many people do it or can, but like
any other skill, you can develop it with practice.
That may well be true, but it's irrelevant to whether one should go easy
on the synchros or not, since the empirical evidence suggests that they
are prone to wear. We can complain about it - and we should - but it
won't change the need to adjust our driving styles to suit.
Some of the reported problems are undoubtedly due to people changing the
oil and using the wrong type. Hyundai transmissions require GL-4 oil,
which is not commonly available at auto parts chain stores and
department stores. Using the commonly available GL-5 oils or those
labled "universal" will cause premature synchro wear in a Hyundai tranny.
Older Hyundai transmissions were also prone to bearing wear, but I don't
know if that's true for the current ones.
True, but only to a point. Wear is going to occur in any tranny, but when
the wear does not affect the tranny over its useful life, then that amount
of wear is neglible. That's what I'm talking about. Upshifting and
downshifting just don't wear out syncros prematurely. I've consistently
driven vehicles over 200,000 without having to replace syncros. I'm sure
they were worn, but who cares? They were no more worn than anything else on
the vehicle at that point.
Consider the normal shift process. Accelerate, simultaneously take your
foot off the gas and press in the clutch. From that point on the engine
rpm's do not match the speed of the tranny. That's why we have syncros.
Agreed, you can match them and I've done that millions of times, but in
normal driving, 99% of the population just does not do that, and the manual
tranny is no worse off for it.
This is the only point I would strenuously challenge Brian. I disagree that
there is empiracal evidence of excessive wear to the syncros. I do agree
they are a wear item, but that's life. They don't wear out in tens of
thousands of miles. Like I said, I've driven them hundreds of thousands of
miles. There does come a point where worrying about wear just isn't worth
the worry. The rest of the car is going to be junk at the point where you
do enough damage to the syncros simply by downshifting.
I agree. Using engine braking to help save brake wear makes a
measurable savings on brake pads and shoes while incurring an
immeasurable amount of wear on the clutch and transmission. I've never,
ever worn out either a clutch or a transmission and I've driven standard
shift for 30 years up to and including OTR rigs.
My standard shift cars get nearly double the brake pad life of my
automatic vehicles so I know the savings there are real. Since I've
never replaced either a clutch or a transmission, the cost there is zero
for downshifting and using engine braking.
How many Hyundais have you owned? Hyundai transmissions ARE prone to
synchro wear. The sychros in my Excel's transmission only lasted about
30K miles before grinding in 1>2 and 2>3 shifts became common. The
rebuilt transmission suffered the same fate, so it wasn't a fluke. I've
been driving standard transmissions for over 30 years and this was the
first car I ever had a synchro problem with. If you follow the any of
the Elantra sites, you'll hear plenty of tales of worn out clutches and
synchros. Do whatever you want with your car, but you may not like the
You don't practice on your own car. Yo do that stuff on rentals or cars at
work. When I was 17, I used to deliver groceries in a '58 Chevy Sedan
Delivery (windowless station wagon) and got to practice all sorts of
shifting techniques, braking in snow and ice, other things I'd never want to
do in my own vehicle.
I wonder how many people under about 50 know what you are talking about.
I suppose I didn't explain properly. I don't tend to downshift for
braking purposes, I just meant when shifting down from a higher gear,
such as dropping down into 2nd gear after turning a corner or after
slowing for a traffic obstacle.
I've never been a huge fan of engine braking (except on steep hills
such as in colorado, but I've never been there with this car). I
always figured that there was extra clutch wear (engaging it extra
times every time you decelerate), and I can do brakes many times over
for the cost of what I'd have to pay someone else to replace my clutch.
That's the theory anyway.
True, but it's common to slip the clutch when downshifting for the
purposes of engine braking, in order to avoid sudden deceleration and
the jerkiness it can cause, particularly in low gears. That does wear
the clutch considerably. I assume that's what he's referring to.
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