Y1 tranny w/ lsd. Like the topic says it only grinds in third and fourth gear in high rpms. Is this a serious problem, or what?

 

syncros in your tranny are bad

 

mine does it into 4th.. not a big deal its just gonna grind and grind untill you fix it

 

not to jack your thread man, but mine does this too.

What syncros can be used from american trannys for the Y1 with lsd since id really like to get this fixed. Would it change the ratios at all?

 

Also is it easy to fix this problem and how much would the syncros cost?

 

my buddy told me just to buy a new one and send my old on in later cause it could be pricey, so what im doin is gonna buy a new one send mine in and if it happens to the the new one ill just send that in..

 

All you need is some Synchromesh.

 

What brand or kind need more info.

 

Go to the GM Dealer, I bought the friction modified stuff. I had some nasty grinds with Redline, my tranny loved the Synchromesh...

 

The reason your tranny has grinds (try not to take this wrong) is because you don't know how to "heel toe" rev-match your downshifts. If you learn how to use all three pedals at once you should not have this problem. I had an integra years ago and shifted the car like crazy. When the ening died at about 240K miles the tranny still shifted almost like a new one. Not a single grind. I have never worn out a synchro including putting 80K miles with a few K track miles on a tt supra. Practice your downshifting skills and don't kill it on the upshifts either.
Barry H.

 

why would you need to push the gas while your downshifting? i know your supposed to match your rpm on each downshift but...?

 

Here is a long explanation which has applies to on track situations but still dicusses why you chew up drivetrain components like synchros when you don't rev match downshifts. I sold my tt supra with 147K miles on it having put 80K miles on it myself with a bunch of Solo 2s, and several thousand miles of track events on the tranny and clutch. My synchros were still very good (getrag tranny is OEM) and was still on the same clutch when I bought the car. If the prior owner didn't change it I was on the original clutch! Here is the long version below with the obvious note the author is discussing a RWD car :

Downshifting - In order to accelerate quickly out of a corner, the car
must be shifted to the appropriate lower gear before the corner.
Naturally this should be done as late as possible, preferably at the same
time that you are braking for the corner.

This presents a small problem. If you are braking and shifting, your
right foot is on the brake, and your left foot is on the clutch. Without
throttle input, the engine RPM's will drop quite low and when you let the
clutch out, you will 'pop' or jerk the rear wheels. This sudden jerk acts
as an additional brake, but could cause the rear wheels to exceed their
traction limit and cause a skid, to say nothing of the potential damage to
either the engine or drivetrain! The solution lies with "heel and
toeing". This technique during downshifting helps us achieve smoothness,
while eliminating possible clutch slippage and extending the life of the
transmission.

This technique is one that should be thoroughly practiced until it becomes
second nature. It can not be learned on the track. Here's how it goes:
1) As you begin braking with your right foot, depress the clutch with your
left foot. (so far, just like normal). 2) With the clutch all the way
in, two things happen: move the stick shift into the desired lower gear,
and rotate your right foot so that the ball of your right foot is still on
the brake, and your heal is over the gas pedal. 3) Now "blip" the
throttle to raise the RPM's by about 1000 - this matches the RPM's. 4)
Now release the clutch, and ease off the brake.

Here's a real life example. You're going down the back straight 100mph,
4th gear, and 6000rpm. Ahead is a 90 degree right turn coming up quick,
and the exit speed of this corner is 60mph. Exiting the corner at 60mph
in 4th gear doesn't work, so you have to downshift. Just before the
corner, brake in a straight line. In just moments you've slowed to 80mph,
and you should now depress the clutch. Now rotate your right foot, shift
into 3rd gear, and blip the throttle. While you are rotating your foot
and blipping the throttle, you are still slowing down, and you are now
going about 60mph. When the tach reaches about 5500rpm, let the clutch
out smoothly, and ease off the brake. That's it. Now go out on the
street and practice! (you can practice 3rd to 2nd gear downshifts on the
streets - 3rd gear and 45mph into a 2nd gear, 20mph corner.) This example
only works if you are turning 6000rpm in 4th gear at 100mph and 5500rpm in
3rd gear at 60mph, but you get the idea.
=-=-=-=
Here's mine from a previous post:

The idea of heel and toe downshifting is to allow maximum braking force
-while- selecting the lower gear. Consider that you are braking hard
coming into a corner. If you now use your feet just on the brake and
clutch as you downshift, you will generate a lot of engine braking as you
release the clutch. With the tires already at a limit under heavy braking,
this engine braking can cause the driven end (front in FWD...) to lock
up, thus loosing traction. By matching revs, you select the lower gear
without upsetting the car's balance. And now, you can accelerate out of
the corner. :-)

As an aside, you may not necessarily have to match revs -exactly- as you
release the clutch. The idea it to prevent engine braking forces. As you
prepare to release the clutch, you can blip the throttle with the right
half of your foot to a point -above- the matching RPM. Then, as rpms fall,
release the clutch. As long as you are a bit above or equal to the
matching RPM, you will be OK. There should not be a significant amount
change to the car's balance generated by bringing the engine rpm -down- to
the needed speed. This modified technique still requires good timing and
coordination, but you don't have to concentrate as hard on the required
RPM.

I find that the rev-matching idea underlying the technique of heel and toe
downshifting is useful even when I'm not burying myself into a corner... I
always Rev Match when I downshift (preparing to pass, for example) as a
method of minimizing driveline shock.

Also, please be prudent if you decide to attempt to learn these techniques.
Rely on -your- judgement, not my opinions...
=-=-=-=-=

I use it all the time for the practical purpose of prolonging the life of
my clutch. I can't believe how many people downshift into a lower gear by
basically just dropping the clutch and FORCING the engine rpm to rise up.
With heel and toe, you tap the gas while simultaneously braking (all with
the right foot) to "pre-raise" the engine rpm before dropping the clutch.

If you are just downshifting in preparation to pass or the like, you may
not need to really Heel and Toe because you aren't on the brake. You can
Rev Match the downshift by tipping into the throttle a bit when declutching
so that the revs are matched.

In each case, the result: the clutch engages with the engine (and thus the
flywheel) already matching the same rpm. In principle, if you were
perfect at it, there would be no clutch slippage at all. Hence: no clutch
wear. Try it, heel and toe and rev matching become second nature very
quickly. Save your clutch and have fun downshifting at the same time!


__________________

 

you got the wrong idea but thanks anyway. Its when I am shifting up. From 2nd to 3rd at 6000 rpms it wont grind but at 7600 it will grind.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSVTEC 91 Civic &raquo;</TD></TR><TR><TD CLASS="quote">Go to the GM Dealer, I bought the friction modified stuff. I had some nasty grinds with Redline, my tranny loved the Synchromesh...</TD></TR></TABLE>

Or just go to autozone and by the Pennzoil synchromesh, same thing but cost a hole lot less. Also these products might get rid of the grinds, but what your really doing is hiding the problem. If you trans grinds, no fluid is every gonna permanently fix it.

 

whenever i do a serious downshift, like 5th to third to pass on the highway, oh shift into 1st when going like 25 for fun acceleration, i always double clutch, for anyone who doesn't know, its essentially matching the transmission's internal shafts and gears speed so the synchros are already in unison. Therefore they don't need to synchronize so it saves the life of the tranny.

 

i got mine from a someone i didnmt make mine grind i know how to rev match... im gonna try some synchromesh shhtufff


Do i add this snychromesh like i do lucas, lucas+oil quart of each

 

Here's the deal. Contrary to what many people think, the job of a synchro is NOT to bring the gears to their proper speeds before they mesh. The gears always ARE in mesh. Therefore, they always ARE spinning at the proper speeds to mesh. Rather, what REALLY happens when you shift into a gear is that the gear that you shift into becomes 'locked' onto its shaft. For the lower gears, this would be the output shaft. For the higher gears, this would be the input shaft. The other gear (ie the one that the disengagable gear mates with) is permanently locked to its shaft. The job of the synchro, therefore, is to bring the GEAR AND SHAFT to the same speeds so that the spline on the gear and slider will mate easily and not grind. The synchro does this by 'grabbing' a conical surface on the gear in order to bring it to the right speed by friction.

As the synchro wears (which, because it operates by friction, it eventually will), it will not be able to 'grab' the surface as well. And if it does not grab as well, it will not be able to change the speed on the shaft/gear as well. If we are talking about upshifts, it will not be able to slow the shaft/gear as quickly. And shifting at high RPMs requires that the speed be changed ALOT more than at low speeds. This is why a grind is always noticed first when shifting at high RPMs.

 

also shifting slower will result in no grindage plus let the tranny last longer, just get more power to make up for the time lost shifting. j/k easier said than done.

 

So basically even though the syncromesh fluid will fix the problem its not really fixed and in the long run you will just have to buy new syncros for your tranny.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSVTEC 91 Civic &raquo;</TD></TR><TR><TD CLASS="quote">Go to the GM Dealer, I bought the friction modified stuff. I had some nasty grinds with Redline, my tranny loved the Synchromesh...</TD></TR></TABLE>

Or you can do a search here and see the various syncromesh threads.

 

these guys http://www.gear-speed.com/ specialize in rebuilding JDM trannies.

 

In the long run yes, if your synchos are that bad that the trans grinds, well if the teeth are that bad on the synchos, fluid is not gonna add metal to to those teeth.

 

how many quarts should i buy...2?

 

3, Interesting the creating of the topic is banned now.