• Protip: Profile posts are public! Use Conversations to message other members privately. Everyone can see the content of a profile post.

Today I Ground Down Some Gears!?!

Joined
14 March 2005
Messages
78
Location
CA BAY AREA
I haven't done this but one other time....I was "launching" from stop and revved up to about 8,000rpm in first, then went to quick shift using the clutch of course into second and bzzzzzzzzzzzzzzz

A little bit of grindage. Any one else ever learned this lesson? Is it terrible to happen? Any thoughts or suggestions.

I wasn't racing just trying to get up to vtec thru all the gears.
 
NSXVURGIN said:
I haven't done this but one other time....I was "launching" from stop and revved up to about 8,000rpm in first, then went to quick shift using the clutch of course into second and bzzzzzzzzzzzzzzz

A little bit of grindage. Any one else ever learned this lesson? Is it terrible to happen? Any thoughts or suggestions.

I wasn't racing just trying to get up to vtec thru all the gears.

It is your synchros - if it is only a few times I wouldn't worry about it. It happens occasionally when they are slightly worn, and more frequenty when the tranny is cold. A tranny flush with synchromesh might help. It it doesn't, you either get to live with it or tear open the tranny.
 
A friend of mine mentioned maybe the clutch...The clutch was replaced around 58,000 and now has 83,000

But it doesn't slip when getting on it. Maybe my own "synchros" were off, foot to arm.??
 
It is not the clutch, it is the synchros. Syncros are brass (I think) fittings in the transmission that help match the speed of the 2 shafts. The faster you move the lever to change gears (assuming you are not rev-matching) the harder they work. When you hear that grinding, it is becuase the synchros have not done thier job. Shifting slower, especially when cold will help.

I am far from the expert on this, hopefully someone will step in and fill in any holes that I may have missed.
 
Not too many holes, White94. The sybchros are a brass alloy. Each of the 5 speeds (and reverse) has two gears. One fixed, one freewheeling (when not in use) The synchro sits on a shoulder on the 'loose' gear and has a small film of oil under it. When you shift, the slider ring (which has internal teeth) slides over the synchro which slowly locks over the gear shoulder, pushing out the oil thru little grooves on its inner surface, and temporarily stoppimg the gear so it can also recieve the slider. Directly beneath the gear shoulder on each gear is a small set of teeth, and it is these teeth that actually join the slider. Half of the slider sits over the gear, and half stays on its hub, which is slpined to the shaft. This is how the two shafts are 'joined'.

Ever miss a shift and notice that no matter how slow you try the same gear a second time it still grinds? This is because you jammed the synchro onto the shoulder, and with the two locked, the slider is is hitting a spinning wall of teeth. Selecting a differant gear allows the two to unlock.

It is actually the inner teeth on the slider that wears the most and causes the most shifting problems. Also, the synchro has a mild steel ring, made of thin wire (< 1mm dia.) that wraps around the top of its little teeth and meets the slider first, helping the slowing process. This little part causes most grinding, or gear clash, when its outer surface is worn flat, and the slider goes right over it as if it wasn't there. It is only then, if you don't make any repairs, that the synchro needs replaced. And what wears out on the synchro is the little area of oil wipes between it and the gear shoulder. When these are diminished, two things happen- the distance between synchro and gear shoulder become too small (< 1.1 mm) and / or not enough oil moved out quick enough.

As to the original question, I would do nothing, worry about nothing, except to remember not to shift too quickly on a cold trans. The thick oil does not move out of the synchro / shoulder quick enough and this is aggravated by the thicker oil's drag on the gear.

Sorry if thats TMI. (TMCoffee)
MB
 
Back
Top