woodward Posted August 17, 2011 Report Share Posted August 17, 2011 Hello The clutch in my TR4 went this morning (loud bang followed by no drive and a ride in a recovery vehicle), it's a TR4A diaphragm clutch that I only installed recently and which has limited miles on it. It's a real pain to have to pull the gearbox again and would like this to be the last time for a while! I have read in the past that not all clutches are the same in terms of quality etc. Can someone advise which supplier is preferred for clutches? Also, should I switch back to the old spring clutch? I thought that I was upgrading by going for a TR4A clutch but none of my previous TR4s or TR3s have ever had a clutch fail. Any advice gratefully received... Thanks Mules Quote Link to post Share on other sites
stuart Posted August 17, 2011 Report Share Posted August 17, 2011 Hello The clutch in my TR4 went this morning (loud bang followed by no drive and a ride in a recovery vehicle), it's a TR4A diaphragm clutch that I only installed recently and which has limited miles on it. It's a real pain to have to pull the gearbox again and would like this to be the last time for a while! I have read in the past that not all clutches are the same in terms of quality etc. Can someone advise which supplier is preferred for clutches? Also, should I switch back to the old spring clutch? I thought that I was upgrading by going for a TR4A clutch but none of my previous TR4s or TR3s have ever had a clutch fail. Any advice gratefully received... Thanks Mules There were some faulty clutch plates around a while ago that let go around the centre section of the plate. It may be that you had one of those fitted. 4a clutches are generally pretty good though lighter than the 2/3/4 spring type. Stuart. Quote Link to post Share on other sites
woodward Posted August 17, 2011 Author Report Share Posted August 17, 2011 Oh dear, I now have the gearbox cover off and there is a large crack in the casing just behind the bell housing. I am assuming that when the clutch let go that it cracked the casing. So looks like a gearbox rebuild as well as a new clutch is required.... Luckily I have a spare non overdrive box. Anyone know of someone either in the Essex or Hampshire areas that would be able to convert my non overdrive box into an overdrive box using the appropriate bits from the broken overdrive gearbox....? Thanks Myles Quote Link to post Share on other sites
RogerH Posted August 17, 2011 Report Share Posted August 17, 2011 (edited) Is it the clutch that has failed or part of the drive chain = prop shaft/drive sfaft UJ's etc. These can go with a bang and give no drive . Also the gearbox and overdrive contain things that go bang. Roger PS just read your last post (over lap in pressing buttons) why would the clutch crack your gearbox. Have a good investigate before jumping to conclusions. Edited August 17, 2011 by RogerH Quote Link to post Share on other sites
stuart Posted August 17, 2011 Report Share Posted August 17, 2011 When I got my 4a it had three large holes in the bell housing where a clutch had exited through the side! So they can do some damage if they let go. A crack in the main casing does sound like a terminal failure inside, possibly layshaft front end where they wear the end bush. Definite need for major investigation inside the box Im afraid. Stuart. Quote Link to post Share on other sites
RandallD Posted August 17, 2011 Report Share Posted August 17, 2011 Myles- Sorry to hear of your mishap - I agree, this does not sound like it is related to the clutch but something more serious in the gearbox unfortunately - hopefully the mainshaft is still in decent shape so you can swap the overdrive over to the spare box. If you visit Texas again give me a call. Randy Quote Link to post Share on other sites
BrianC Posted August 17, 2011 Report Share Posted August 17, 2011 Looks like the clutch itself is not your only problem now, but if you do replace it, then the earlier spring clutch is stronger, lasts a lot longer and there are no rogue replacement units around (AFAIK). It's probably only worth using the diaphragm type if you have a weak left leg or your other half drives the car! Quote Link to post Share on other sites
RogerH Posted August 17, 2011 Report Share Posted August 17, 2011 Brian, as an aside could you fit a brake servo in the clutch system - I'm sure I've heard of this. Roger Quote Link to post Share on other sites
stuart Posted August 17, 2011 Report Share Posted August 17, 2011 Brian, as an aside could you fit a brake servo in the clutch system - I'm sure I've heard of this. Roger Yes you can. Tony (Bald Rick) has one on his 6. Stuart. Quote Link to post Share on other sites
woodward Posted August 18, 2011 Author Report Share Posted August 18, 2011 Thanks for all your advice. Gearbox is now out of the car...in two pieces (see pics). Clutch looks to be okay. Any ideas on what could have caused this to happen...? Myles Quote Link to post Share on other sites
stuart Posted August 18, 2011 Report Share Posted August 18, 2011 Ouch! Triumph did have this problem on the earlier TR boxes hence why these have the extra webs on either side. Never seen a later one break like that without some serious abuse. Do you know the history of the car or that gearbox? Stuart. Quote Link to post Share on other sites
RogerH Posted August 18, 2011 Report Share Posted August 18, 2011 Myles, can you take another pic square onto the crack surface on the bell housing. The surface texture of the crack surface can give info on the failure. Roger Quote Link to post Share on other sites
BrianC Posted August 18, 2011 Report Share Posted August 18, 2011 I don't think JB Weld will fix that one! Quote Link to post Share on other sites
RandallD Posted August 18, 2011 Report Share Posted August 18, 2011 Amazing - thankfully it didn't grenade worse than that - just speculation, but did you have a lock up situation with the gearbox, so the case itself was the weak link? I'm wondering what you'll see inside the case. The fact that your clutch looks ok but had no power to the rear wheels suggests something bad happened with the laygear perhaps. Quote Link to post Share on other sites
woodward Posted August 18, 2011 Author Report Share Posted August 18, 2011 Here's the best picture I have of the crack. Unfortunately the car's at my sister's house and I'm not so unable to take any better photos at the moment. Can you tell anything from this? Myles Quote Link to post Share on other sites
RogerH Posted August 18, 2011 Report Share Posted August 18, 2011 Hi Myles, the last pic is not so good. If the case has been going duff over a long period then what you need to look for is the texture of the crack surface. If it is clean and crisp and the edges are sharp then this suggests that it failed suddenly - the final bang. Any area that is shiney and polished has been cracked for a while and the two surfaces have been rubbing together. The edges probably will not be sharp. Any area that is black/dirty has been cracked for a long time and probably the start area of the crack. Cracks tend to start at shapr changes of section or cut-outs. Have a very close look at the surface and see if you can see any radial marks propagating along the crack surface - these are called beach or tide marks - and it shows the crack moving. When the crack is big enough you lose the required strength and it goes bang. What good will the crack info give- perhaps identify the cause. Your box may actually be OK but the case had a nasty propagating crack. Quote Link to post Share on other sites
Alec Pringle Posted August 18, 2011 Report Share Posted August 18, 2011 The only times I've seen a case like that resulted from internal failure of the gearbox - as in the box locks up, tries to rotate, and rips off at the rearward end of the bellhousing before disintegrating into shrapnel internally. Enlarging your photos and looking at the shape of the fracture, my hunch is that's what's happened in this instance. Have you tried rotating the input shaft to see what happens ? A failure farther along the drive train is more likely, at least in my experience, to destroy the diff rather than rip the 'box off the bellhousing. Cheers, Alec Quote Link to post Share on other sites
Guest ntc Posted August 18, 2011 Report Share Posted August 18, 2011 Or in the past it has had a crash bang etc Quote Link to post Share on other sites
woodward Posted August 18, 2011 Author Report Share Posted August 18, 2011 The gearbox had only been in the car for less thna 500 miles. The guy I bought it off said it had been rebuilt. The box gave up when I was doing 70 mph on the M3 - loud bang followed by a loud rumbling noise. The car did have some drive when I was on the hard shoulder - if you started the car in gear it would move forward very slowly, if you tried to increase speed the rumbling would come back. Unfortunately I didn't have time to look inside the box this morning. I did turn the input shaft in most of the gears though and it turned ok. Myles Quote Link to post Share on other sites
RogerH Posted August 19, 2011 Report Share Posted August 19, 2011 If the box didn't lock up and the drive/propshafts are all ok then it is possible that a progressively growing crack gave up the ghost when given 100BHP to contend with. There is always a torsional force in the bell housing during normal driving. It has to take a fair percentage of the output of the engine. Roger Quote Link to post Share on other sites
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