b20civic

Can anyone give me any ideas why my third gear scratches/grinds when i shift from 2nd to 3rd slowly/normal driving, but when i shift a little quicker, or when i speed shift, it wont grind at all? When i shift fast it is smooth as hell, just like every other gear on my transmission. But when i drive the car normally, slow my shifting down for daily driving it will grind noticably. I have in the past 2 months replaced both my clutch master and clutch slave cylinders, bled it three times, and tried several different adjustments on the clutch master cylinder pushrod. But have had no luck. I run honda MTF in my transmission. About 5 months ago, i replaced 3rd/4th synchros sleeve set. I also replaced the shift fork at that time. I just think that it seems odd that i can rev it out to the rev limiter and speed shift, with absolutly no grinding, but when i shift at around 3500 to 4000rpms at a slower, normal driving shift, it scratches. Any ideas?? Thanks

Spade

Syncros'

b20civic

you really think that i trashed my 3rd gear synchros again after only 5 months of use? Also, last time my synchros were bad, it would grind worse the higher the rpms i would shift at. Not get better and go away when i revved higher. Thats why im thinking that it could be something else. Any other opinions. Could the transmission being overfilled cause this problem? I was told that i may have my transmission overfilled. thanks

notstock93

Im not sure, but it might be just you shifting TOO slow. I mean, if you dawdle in between gears, you can grind the **** out of your tranny. I.E if your really slow going from nuetral to any gear, prepare to hear some bad noises. Other than that, a fair guess would be your clutch needs adjustment.

Quick 200k Mile Motor

Do you have a lightened flywheel also?
First off your 3rd gear synchronizer is bad, here is what I think is happening..

When you change gear slow, there is more time for the engine to decelerate.
The 3rd gear synchro is worn so it can't synchronize the dramatic change in layshaft speed for the next upper gear.

Try this, when shifting to 3rd, keep the engine speed up instead of letting it drop a lot. Slightly below where you left off (minus 500-to-750rpms is ok, if you're shifting at 3500rpm keep it at 2750). This is harder to do if you have a light flywheel, the engine decelerates fast.

If it still grinds, your gonna have to double clutch.
*press in the clutch
*take the shifter out of gear
*while its out of gear, blip the right amount of throttle (clutch pedal must be out, and the shifter must be out of gear). This brings the shaft to speed, finding the right amount of throttle in between is the hardest part.
*press in the clutch
*put shifter back in gear
*let go of the clutch.

You're basically guessing what the engine speed will be (after changing gear)
and bringing the shaft to that same speed before changing gear.

b20civic

okay, how, can i tell if i need to install a new 3rd gear also? I do have a lightened flywheel, and what you described makes a lot of sense to me. Ill have to give what you told me to do a try next time i get in the car. Ill let you know. Thanks

ERIK

vadim

the teeth on third gear are worn down so the tranny does't masth the gears right it ok my firends crx does that in second and third

b20civic

well, it doesnt matter if i keep the rpms up, where you specified. It will still grind. So i dont think it is because of my lightened flywheel, nor because i shift TOO slow. It happens when other people drive my car, and shift normal also. How can i tell if it is the gear, or the synchros?

hybridEj6

mine grinds from 2nd to 3rd when i speed shift, but its weird when i used a chipped skunk 2 computer and shift at 8400 it doesnt grind i think its just how the sychros are worn and how they line up at different engine speeds, mine doesnt grind when i shift slow, havent trieded shifting slow with the chipped p28

ejprimo

my thrid gear shifts fine when i let the rpms drop but when im in the upper rpm ranges my 3rd gear grind.