r1_pete
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| posted on 24/11/08 at 04:57 PM |
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Any gearbox experts out there??
I recently posted about a noisy Zetec, it isn't the engine its the MT75 gearbox.
At tickover, in neutral, if I let the drag on the gears turn the output shaft, it is silent, if I stop the output shaft I get a regular metallic
knocking. In gear the knock is intermittent, but does seem to change frequency depending on the gear.
In gear or in neutral, as the revs rise the knock dissapears.
The noise appears to be comming from the front section of the box.
Any ideas? can the MT75 be re-built? I'd rather get it rebuilt than replaced as I've modded the housing for a rear mounted clutch slave...
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mookaloid
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| posted on 24/11/08 at 05:05 PM |
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it's not the release bearing rattling on the clutch cover is it? 
"That thing you're thinking - it wont be that."
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jacko
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| posted on 24/11/08 at 05:18 PM |
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don't let me get you on the wrong track, but i had a manta years ago and it did the same thing the 5 gear shaft made all sorts of noise's
if the engine timing was set wrong
Jacko
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r1_pete
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| posted on 24/11/08 at 06:28 PM |
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I did think the rocking of the engine due to uneven tickover might be causing it probably poor timing, been playing megajolt...
With the car running, I cannot stop the noise from the clutch arm, i.e. pressing it against the clutch to take up any play.
I can re create the noise by having it in gear, with someone pressing the clutch in, and turning the output flange backwards and forwards.
Maybe I'll leave it for now and get on with something else....
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rusty nuts
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| posted on 24/11/08 at 07:07 PM |
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Difficult to say without hearing the noise but it may be a gear chipped ? Does the noise stop if you put it into gear with the engine running and
clutch pushed down?
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r1_pete
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| posted on 24/11/08 at 07:15 PM |
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Yes, in gear clutch in, output shaft held still, noise dissapears, in fact pressing the clutch stops the noise, but only when its fully disengaged and
the centre plate is free of the flywheel/pressure plate.
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jacko
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| posted on 24/11/08 at 07:55 PM |
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How about the springs in the clutch plate [ broken ] ?
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big_wasa
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| posted on 24/11/08 at 08:44 PM |
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What thrust bearing did you use ?
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r1_pete
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| posted on 24/11/08 at 09:07 PM |
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The clutch springs were ok, brand new clutch.
I've used the Siera twin cam thrust bearing and clutch, had the zetec flywheel redrilled to take it.
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C10CoryM
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| posted on 25/11/08 at 03:07 AM |
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Probably be a dead roller in the bearing between the input shaft and the main shaft. Some reason they tend to go square when they fail and make a
knocking noise as they go around. Should be silent in 4th if so.
Cheers.
"Our watchword evermore shall be: The Maple Leaf Forever!"
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rusty nuts
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| posted on 25/11/08 at 07:44 PM |
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Don't suppose you turned the input shaft before you fitted the engine?, if so was it knocking then? Has the gearbox been filled with oil ? Way I
see things you can remove the box and sort the fault now or finish the car or at least get it to the stage that you can drive it to assess things?
Not what you want to hear I'm afraid. Just a thought when you modified the box for the clutch did you drill into it? or fit longer bolts ?
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