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Gearbox or diff on the way out?
wheezy - 13/5/08 at 08:13 PM

Driving back from work today I turned a corner and went to accelerate away. 1st and 2nd were fine got into 3rd and there was a loud metalic crunching noise followed by what sounded like a broken shaft clatering away.
I backed of the power and maintained steady revs for a while thinking the gearbox had gone.
about a mile from home i started to use all the gears but not under heavy load. No problems at all.
I have just taken it out again and pushed it hard through all the gears, again no problems. Is the gearbox about to let go or maybe its the limited slip diff. Any ideas?

Dave

mookaloid - 13/5/08 at 08:26 PM

2 choices: either thrash it till it breaks proper or start stripping things to find the culprit....

I expect the second option will be cheaper

r1_pete - 13/5/08 at 08:28 PM

If all seems fine now, had you picked a chunk of crap up off the road and the prop tossed it round the tunnell, or something fallen off and got lodged in a spinning bit till it dislodged when you backed off.

Have a look for tell tale marks underneath before suspecting expensive bits...

[Edited on 13/5/08 by r1_pete]

McLannahan - 13/5/08 at 08:29 PM

My horrible crunch turned out to be a broken gear selector arm. Weld had come away gradually resulting in it eventually coming away altogether. Had a local welder weld it back up for a few quid and never another issue!

wheezy - 13/5/08 at 08:38 PM

quote:
Originally posted by r1_pete
If all seems fine now, had you picked a chunk of crap up off the road and the prop tossed it round the tunnell, or something fallen off and got lodged in a spinning bit till it dislodged when you backed off.

Have a look for tell tale marks underneath before suspecting expensive bits...

[Edited on 13/5/08 by r1_pete]


Not any debris that I am aware of as the car is panelled from front to back with no signs underneath of impact. The prop is about a foot long and is inside the engine bay
The noise must have lasted for a couple of seconds and sounded fairly catastrophic. My imediate thought was that the gearbox was about to lock up.

Hellfire - 13/5/08 at 08:54 PM

Drop the oil and check the sump for any signs of metal then pop the clutch cover and check the basket. Earlier ZX12R clutch baskets were prone to breaking due to lack of oiling. Fingers crossed it's ok though.

Funnily enough Dave, me and our old man were talking about you about 10 minutes ago, wondering how you were getting on. (Before you posted though, so we can't be held to blame)

Phil

wheezy - 13/5/08 at 09:09 PM

Nice to here I aint been forgotten. Say hello to yer old man for me
Unfortunaley dropping the sump and taking of the clutch cover is an engine out job
(the perks of having a mid engine BEC)
I needed to cure the small oil leak round the sump pan anyway.

Dave

charlierevell - 2/6/08 at 04:50 PM

I get this in my 954 blade...
It would seem its not quite a false neutral but the dogs are half engaging. Hence the clatter and the horrible horrible sound!
Makes me shudder when it happens but it only does it on some occasions... I'm wondering wether it may have something to do with the movement on the gear shif rods.

The box was only built in December!

ChrisGamlin - 2/6/08 at 08:07 PM

Sounds like a false neutral to me.

This is what it sounds like when you properly break the dogs, and TBH a false neutral doesn't sound a lot nicer.....

http://www.youtube.com/watch?v=EfQAcgWwOa8

[Edited on 2/6/08 by ChrisGamlin]

wheezy - 3/6/08 at 06:54 AM

Well Ive had the engine out and the sump and clutch covers off. The gearbox looks in tip top condition, no signs of wear and the shift forks are straight as a dye. So it looks like it was me hitting a false neutral as you thought.
At least it gave me a chance to stop the leak from the sump.

Dave