allegro Posted February 24, 2003 Share Posted February 24, 2003 When out of gear and clutch up I get a rattle from the gearbox. Depress the clutch and it goes away. I know this is normal, but a little annoying and I'm sure it's getting louder. Might this be a sign that I need a top up of gearbox oil 🤔 Andy Mac C7 GON 😬 Team Langoustine. Hard Core Prawn here 😬 Link to comment Share on other sites More sharing options...
John Howe Posted February 24, 2003 Share Posted February 24, 2003 By depressing the clutch pedal you are engaging the clutch trust bearing. If it rattles when the bearing is not working and you are not in gear then it sounds like the trust bearing assembly is just chattering from engine vibration. JH Deliveries by Saffron, the yellow 222bhp Sausage delivery machine Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 24, 2003 Share Posted February 24, 2003 This isn't the thrust bearing assembly. It is the lay gears rattling on the shaft. Does it get worse with time? Hmmm. There is no significant wear mechanism, and if there was a lube problem your gearbox would have seized/snapped teeth/rendered itself down to swarf already. What is probably happening is that your idle is getting more erratic, leading to the rattles as the gearshaft is undergoing cyclic acceleration and deceleration. Best way to cure this is to fix the idle so that it is baby bottom smooth, which is possible with an Emerald or similar setup. VHPD engines are very prone to this. Upping the idle to ~1100rpm has very few downsides and tends to smooth things out. Link to comment Share on other sites More sharing options...
allegro Posted February 24, 2003 Author Share Posted February 24, 2003 Bugger, I already have an Emerald. The idle does fluctuate +/- 30rpm from 1000rpm. My battery is on the way out, so this may have an effect on smooth idle. Andy Mac C7 GON 😬 Team Langoustine. Hard Core Prawn here 😬 Link to comment Share on other sites More sharing options...
Robin C Posted February 24, 2003 Share Posted February 24, 2003 Andy, I agree with John above. I KNOW my thrust bearing assembly rattles as I messed up the small rubber thing Caterham fit as an anti-rattle device on assembly. However I do not see the point in replacing this until I have a more major reason to remove the engine/gearbox. I can kill my rattle by just resting my foot on the clutch, without actually depressing it. This has the effect of tensioning the cable slightly, just enough to stop the thrust bearing lever rattling. Can you stop yours this easily? I'm sure what PC says is correct, but may not be necessary in this case. Robin Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 24, 2003 Share Posted February 24, 2003 Yes indeed. There may be more than one rattle in the system. What I do know is that even though I run a completely different clutch/release assembly with a constant contact radius faced bearing on a concentric hydraulic slave, the rattle is the same. My rattle is certainly the gearbox. Link to comment Share on other sites More sharing options...
allegro Posted February 24, 2003 Author Share Posted February 24, 2003 Robin I'll take up the slack on my clutch cable and then try. Thanks Andy Mac C7 GON 😬 Team Langoustine. Hard Core Prawn here 😬 Link to comment Share on other sites More sharing options...
sjwb Posted February 24, 2003 Share Posted February 24, 2003 Absolutely, it is the input shaft gear chuntering against the layshaft gear. The rattle is caused primarily by a non steady idle and second by inadequate (if any) clutch or flywheel damping. Either way this noise is VERY distinct. Steve B Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted February 24, 2003 Leadership Team Share Posted February 24, 2003 They all do that sir ......... Mines done it for years If you rest your foot on the clutch enough to take up the play in the mechanism, ie. crb resting on clutch cover, there's probably little or no change in the noise. But if you increase the revs very slightly you'll find the noise disappears. Back to Peters point ..... I've just fitted a lightweight flywheel and the noise has become noticeably worse 🙆🏻 Stu. Link to comment Share on other sites More sharing options...
Nifty Posted February 24, 2003 Share Posted February 24, 2003 If it's the release bearing doesn't it become more distinct a little below 2,000 rpm if you rev the engine up and then let it drop back. That was how I was told to identify my rattle, which I think is both, as Peter pointed out. Anyway, the point is it is almost certainly nothing to worry about. Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted February 24, 2003 Share Posted February 24, 2003 Std. fitment with every car Sir. Learn to Love it and live with it (bl%dy annoying though it is) Link to comment Share on other sites More sharing options...
rossybee Posted February 24, 2003 Share Posted February 24, 2003 Thank god for that ❗ Mine does exactly the same Ross very black 6spd SuperSport Link to comment Share on other sites More sharing options...
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