Gears Crunch Under Full Accel.

[RedEmblem]

Hey,

Often when changing gears under full accel. I find that the gears crunch as though the clutch wasn't depressed at all. Someone has mentioned it may be the master cylinder but I have know idea. Any help and any ideas what it costs to fix?

Thanks B)

[WHITER33GTS-T]

Mine does the same thing every change, i was told it could be the syncro's in the g/box could be stuffed?

[Bobjones]

Yep sounds like syncros, get them done as this is the cause of many a gearbox failure, as when the syncros go they normally take gear teeth with them, especially at full noise!!!

I would also check your Slave Cylinder which is located on the side of the gearbox, looks like a lever arm and a small rubber boot.

[tdsepco]

When was the last time your gear oil was changed?

[RedEmblem]

The GB oil was recently replaced. Maybe a month ago?

How do I get them repaired? I don't know a great deal about cars. Would they have to be replaced or can they usually be fixed? Expensive?

Thanks.

[Duncan]

If it is your master or slave cylinder causing trouble you would have the same issue getting it into first gear when you are not moving.

To check if it is synchros, try shifting slower. The synchros line up the gearbox to the correct revs of the engine, so if you are in 7000 in 4th and you are trying to get 5th the revs will have to fall to about 5000. The crunch is from the revs not being correct when you push it into 5th.

So, take it out of gear into neutral, wait a moment, then put it into 5th. A good habit is to let the clutch out while in neutral, then push the clutch in again before you push in into 5th. You wont get a crunch if you dont move it from neutral until the revs are right.

Anyway thats a long way of saying the if your synchros are worn you will have trouble changing quickly in higher gears.

And to replace the synchros is gearbox out and rebuilt 500-1000 I guess.

[Busky2k]

Do you know what oil they put in? Its a possibility they put in the wrong stuff and your shifting can suffer.

Also yeah it costs about 1k to get a gearbox resynchroed and u might aswell do the bearings too.

[fLipKnot]

Redline oil is the option for these problems...

Duncan, isn't it bad for the car to be put into Neutral as such high speeds? Heard it is bad for the flywheel or something?

[RedEmblem]

Not sure exactly what oil was used. It was a Castrol though.

I don't think the new oil is the problem though, becauae the car has always done it.

It must be the syncros as the gears are smooth if I take my time.

Does anyone know if Merc. Motorsport can repair gearboxes? I'm taking my car there in a few weeks or so, so i might aswell get them to have a look if they can fix it.

[Taran]

Try the Redline oil first dude. It's much cheaper option than going straight for a reco.