gear change crunch

[jesfirth]

My gearbox has started crunching when shifting up from 4th ot 5th. It is fine when you are driving normally and only occurs when you are "on it" shifting up at high revs on a circuit.

I assume it is the synchomesh going?

Will it break or can I pretty much ignore it.

Other than the gearbox in/out bit is it a big job to sort? ie should I just buy a spare box and shove it in when something is being done - like the slave cyclinder

[itiejim]

Treat it gently and it'll go on for ever.

I'd be inclined to get the 'box rebuilt properly next time you need to have it out. I don't think that they're unreasonable to rebuild and plenty of parts around.

[HarryW]

My understanding is 5th is the weakest gear on the T5 and the first to go, Nickcc's went at fighting torque in 07 when 'on it'. I also understand the gearboxman does a 'stronger' 5th if asked for the rebuilds. I think Steve H has covered this a few times in threads.

[itiejim]

If it's just crunching on the way in on a quick change it sounds like it's just a syncro ring rather than the gear itself.

If the 'box is out though there's never any harm in having an upgrade...

[Duke Thrust]

I have a spare T5 if anyone needs one.

[shpub]

It can also be a sign that the clutch is not releasing correctly. Another possibility is the choice of gearbox oil. I found that with ATF I got no crunch when cold but with 75W synthetic stuff, it does slightly until the box is warmed up and then it is smooth as silk. This was on a brand new rebuilt box BTW.

[trooperiziz]

The cost of rebuilding it now or replacing it with a reconditioned unit if it does break are pretty similar, so personally I would wait until it gets unbearable, it won't cost you much more if the gearbox does lunch itself.

[350Matt]

try changing the oil before you do anything else