Another_Si_Guy

I've got a 99 Si and the stock transmission grinds when I shift quickly going into third, only when I red lined in second. Thats the only time that it ever happens. And yes, I know that I am for sure pushing the clutch all the way in. It's been consistent only with that gear. Any ideas?

Caoboy

Your OMG street racer shifting habits are killing the synchros.

Replace your MTF, make sure it's topped off, and shift more easily and at lower RPM (like 4.5k or lower, like normal driving) to help the synchros last longer, and start reading up on how to replace them.

Former User

/thread

Another_Si_Guy

I've only had the car for 1 year down to the month. And in that year, I've only redlined it in second three times, maybe. I'm not the culprit. The previous owner was neglectful, to say the least. I just want to fix the problem.

Another_Si_Guy

My normal shifting is between 3,000 and 3,500 depending on how quickly I need to accelerate.

Caoboy

Your options will be to rebuild, or replace the transmission.

Master rebuild kit (if your gears are fine, you won't know until you inspect the transmission) would run you 5-700. New bearings, seals, synchros, etc.

If you wanted to replace it, ITR transmissions go for 1k-1700.

You'll want to replace the rear main seal in the engine, as well as the clutch, you're already in there, you might as well make sure you don't have to pull the transmission twice.

tercel95

I paid Synchrotech about $700 to rebuild mine with all new bearings, seals, etc... Cost me another $150 to ship it there from MD to CA. You could also get an LSD thrown in for about another $600.

I also agree with you in suggesting a new clutch, rear main seal while you have the trans out. I also did a new flywheel, axles and clutch slave/master.

Another_Si_Guy

I don't think rebuilding the transmission is necessary because I have a very slight third year grind only when the engine is spinning at 8,000 RPM.

Caoboy

You also didn't know what was causing your transmission to grind.

Start with replacing your MTF, it most likely needs to be freshened up anyways, and make sure it is topped off so you know that something like dirty worn old low fluid isn't the culprit.


If it is still doing it, you WILL need to at the very least replace the synchros. (That's what is grinding RIGHT NOW.)

If you wait, it is only going to get worse, as accelerated wear on the synchros leads to accelerated wear on the dog teeth of the gears and sleeves, which ends up with you having to replace gears. If you stop the problem now, you save your self headache and money.

Another_Si_Guy

Okay I will definitely change the MTF. Could you explain to me how to do that? There isn't a twist off to fill it up.

Caoboy

https://honda-tech.com/transmission-...orial-2443459/

Second picture for reference.

To the 'rear' of the axle there is a bolt. I believe it is a 14 or 17mm, that is your 'fill' bolt.

The bottom bolt under the axle that uses a 3/8" rachet to remove is your drain bolt.



Open the drain bolt, let it drain out like changing the motor oil. Put the drain bolt back in, make sure to put thread tape on the bolt so it doesn't leak. There also may be a crush washer on it IIRC at the moment.

Open the fill bolt, start filling until it starts come out of the fill hole. Stick your finger in and check and make sure it's level with the fill bolt.

Once that is done, Put the car in first gear and drive slowly to get the fluid distributed, then shift into second, 3rd 4th 5th, taking it easy on the gears, making sure everything is fine.

That's pretty much it.

94EG8

The synchros may be worn a bit, but they are not the cause of your grinding. Normally what you'll find is a banged up 3rd/4th sleeve and hub. Sometimes the 3rd gear engagement/dog teeth will be banged up as well (Synchrotech now sells this part separately for about $50) Synchro springs also get banged up and lead to grinding, but it's not the synchros.

The longer you drive it the more likely it is that will cost more to fix later.