Pete Attryde Posted October 19, 2008 Share Posted October 19, 2008 Evening folks, My 300TDi Auto today developed a nasty intermittant knocking, that seems to be coming from the bellhousing area. I have had a quick look through the starter motor hole and checked that the bolts that hold the torque converter to the flex plate are tight (which they are). I couldn't see any signs of damage around the bolt heads. The noise sounds like a bolt head is sticking out to far and touching something. Now the odd bit is it only seems to make the noise at idle in neutral or park and if the revs are raised or the box is put into drive/reverse the noise goes. Also the vehicle drives perfectly normally with no noise. Help please!!!! Pete. Quote Link to comment Share on other sites More sharing options...
Mark90 Posted October 19, 2008 Share Posted October 19, 2008 Now the odd bit is it only seems to make the noise at idle in neutral or park and if the revs are raised or the box is put into drive/reverse the noise goes. Also the vehicle drives perfectly normally with no noise. Sounds just like when the flex plate on my 200 tdi auto was buggered. Rattles at idle but the force of driving jams the bits together so no rattle when driving. Mine was inspected through the little inpection hole at the bottom looking for radial cracks, but on full engine removal found it has split into two concentric rings, drive only provided by the two bits jamming together. Quote Link to comment Share on other sites More sharing options...
steve_d Posted October 19, 2008 Share Posted October 19, 2008 Does sound like the plate but you could also check that you have not developed excessive end float on the crank shaft. Steve Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted October 19, 2008 Author Share Posted October 19, 2008 Does sound like the plate but you could also check that you have not developed excessive end float on the crank shaft.Steve I hope it isn't, as it was fine first thing this morning and then having sat (not running) for a couple of hours when I restarted it the noise was there. from what mark says it is looking likely that it is the flexplate. Pete. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted October 19, 2008 Share Posted October 19, 2008 Exactly the symptoms of my failing flex plate - it rattles at idle under no load because the cyclic speed variation of the engine is greatest - the accel/decel becomes less significant at higher speeds. Mine had fractured around the centre bolts but most of the noise was from the complete shear around each of the four bolts into the torque converter. On my car this was caused by misalignment from poor installation although it must also have the correct gap to the flywheel so it might be worth investigating why yours has gone pop. Mr Ashcroft has an excellent guide to installing these if I remember correctly. Definately best to fix sooner rather than later though - it could damage the torque converter face if you let it get too bad. I found by dropping the props I could shove the gearbox back a few inches and slide the plate up into the gap. Some pics for your perusal. One of the fractures around the edge bolts told me it was time for the big yellow taxi. The whole plate after I'd wrestled it from the car. Closeup to show it wasn't just the edge bolts that were having a bad day out. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted October 19, 2008 Share Posted October 19, 2008 Yep, man in bellhousing with hammer he banging to say buy new flex plate TC's one is spectacularly f***ed, usually they just break around the centre boss. Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted October 20, 2008 Author Share Posted October 20, 2008 <snip> it might be worth investigating why yours has gone pop.<snip> I suspect it has failed as it has done 140,000 miles behind a rattly old diesel, although I did have a new gearbox about 5 months ago (I inspected the flex-plate then and could see no obvious signs of cracking). I did check the clearances etc at the time of fitting the new box and all was within spec. Pete. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted October 20, 2008 Share Posted October 20, 2008 I bet you wish you had put a new flex plate now though, Pete ? Mo Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted October 20, 2008 Author Share Posted October 20, 2008 I bet you wish you had put a new flex plate now though, Pete ? Mo Absolutely Mo, especially as I can't get the last 2 bolts undone on the bell housing . Ashcrofts have recieved a call and a new flex-plate should be with me tomorrow . Need food . Pete. Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted October 20, 2008 Author Share Posted October 20, 2008 Well after a 3 hour struggle to get the last bell housing bolt out the offending item is out. do you think it's bust Hopefully the new one will rock up nice and early tomorrow and I can stick it all back together. I am begining to think this might have been on it's way out when I changed the box, as all the damage was invisible until i tapped the centre which just fell out. need more food Pete. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted October 20, 2008 Share Posted October 20, 2008 Sikaflex? That's a good one, and as you say, impossible to spot from below. At least you know what it was, it's not too expensive and you're most of the way there already. As I said, it's important to make sure it's lined up exactly parallel to reduce the amount of flexing it has to do. Mine had a 3mm bracket trapped between the bellhousing and flywheel housing, hence the radical patterns in mine. To be fair, if it does another 140,000 you can't complain too much Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted October 20, 2008 Share Posted October 20, 2008 Wow Pete.. You are gonna be a gearbox removal / fitting expert real soon matey ! Shame to see it's gone so soon after the last look inside the bellhousing ! Hope all goes well with the installation. Neil Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted October 20, 2008 Author Share Posted October 20, 2008 Wow Pete..You are gonna be a gearbox removal / fitting expert real soon matey ! Shame to see it's gone so soon after the last look inside the bellhousing ! Hope all goes well with the installation. Neil Cheers Neil, I probably should have replaced it when I had all in bits the first time but being skint and having inspected the flex-plate at the time I thought it would be ok . In hind sight even if it had been cracked then I would not have seen it as all the damage is hidden behind the centre boss. Such is life, at least I can do the work myself so save on the labour costs. At least most of it came apart easily and I have managed to slide the boxes back just enough without completely removing them. roll on tomorrow. Pete. Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted October 21, 2008 Author Share Posted October 21, 2008 Well just to bring this to a close. New flex plate arrived at mid-day. Five hours later everything is back together and working and the mysterious squeak that has been bugging me for months has disappeared, in fact the whole thing sounds so much quieter it's amazing. Even SWMBO commented on how much nicer it sounds . Thanks to everyone who helped to confirm my diagnosis and Ashcrofts for having the part in stock available for next day delivery. Pete. Quote Link to comment Share on other sites More sharing options...
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