Shad Posted June 25, 2008 Share Posted June 25, 2008 Just had a troublesome journey back from Silverstone. I have a 6 speed gearbox and had a couple of occasions where I came to a roundabout and couldn't select any gears at all. Eventually after some jiggling it freed up and I could get a gear. I've limped home, changing down gears is usually ok but going up is usually problematic, either stiff or blocked. Clutch bite is ok but clutch is on the way out, not anywhere near as grippy as it used to be and the first inch of travel is much more spongy/springy than it was a few months ago. When the lever is in neutral it is still dragging a gear quite often so the car creeps forward while making the usual lay shaft rattle a bit more loudly (if that makes sense!). I really really really hope it's the clutch, but I'm also thinking it could be a selector fork or the linkage. Can anyone help me diagnose this please??!! Cheers Simon niknak.org Link to comment Share on other sites More sharing options...
Rowland Cook Posted June 25, 2008 Share Posted June 25, 2008 probably need more details, type of car(superlight HPC ???), engine, hydraulic or cable clutch etc. Early Caterham 6 speeders were problematic but tended to go ping in a big way rather than progressively get worse. Regards Rowland Link to comment Share on other sites More sharing options...
Shad Posted June 25, 2008 Author Share Posted June 25, 2008 It's a 2002 car, 1.6 K-series Supersport, 6-speed from factory, cable clutch. My dad and I are both thinking selector fork(s) but who knows... either way it all needs to come out, which could be fun in our single garage Edited by - Shad on 25 Jun 2008 17:36:10 Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted June 25, 2008 Share Posted June 25, 2008 Does sound like clutch fork - DP's gave out on the IOW in his 21. 7 related photos Link to comment Share on other sites More sharing options...
Mick Day Posted June 25, 2008 Share Posted June 25, 2008 When the lever is in neutral it is still dragging a gear quite often so the car creeps forward When this happened to me the gears had started to "pick-up" on the main shaft. All sorted by R&R but box has to come out for this. If the clutch fork was bent I don't think you'd get "drive" in neutral. However it could be a combination of clutch/fork/gearbox problems all at once I suppose. If it's any consolation this was my 1st introduction to removing an engine. Good luck. Link to comment Share on other sites More sharing options...
Shad Posted June 26, 2008 Author Share Posted June 26, 2008 Bugger ☹️ What's the clutch fork? Is that inside the gearbox or is that part of the clutch? Time to start searching for 'how to remove the engine' I guess! Simon niknak.org Link to comment Share on other sites More sharing options...
Mike Biddle Posted June 26, 2008 Share Posted June 26, 2008 Problems changing up but not changing down does not sound like a clutch problem, that would more likely be the other way around. Anyway, regardless of whether it's gearbox or clutch its an engine out job, and since you suspect the clutch anyway it would be a good idea to replace it anyway as well as sorting the gearbox. Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted June 26, 2008 Share Posted June 26, 2008 It's the lever that sticks out of the bellhousing that the cable attaches to. Basically it pivots at the bottom and carries the clutch release bearing, which it shoves against the clutch when you press the clutch pedal. Still engine out job ! 7 related photos Link to comment Share on other sites More sharing options...
millsn Posted June 27, 2008 Share Posted June 27, 2008 I've had a failed clutch do this. The springs were falling out of the plate, I thought diagnosis was likely to be a problem! Eventually i couldn't select any gear other than first and had to pull it out of gear once I got home to avoid rearranging my back wall in the garage. Link to comment Share on other sites More sharing options...
Shad Posted June 28, 2008 Author Share Posted June 28, 2008 Thanks for the suggestions, should have it out today or tomorrow for a better idea. Simon niknak.org Link to comment Share on other sites More sharing options...
Shad Posted June 29, 2008 Author Share Posted June 29, 2008 I'll be happy if I never have to take an engine out again. What a nightmare. There was much swearing at the stupid stock manifold, the stupid Apollo tank and the stupid alternator. Anyway it's all out now. There's very little meat left on the clutch and the springs are all lose. The CRB spins freely but there's a lot of play, and the clutch fork looks ok (no obvious bends in the wrong places or cracks). So do I send the gearbox off to R&R or just get a new clutch and CRB and cross my fingers? Simon niknak.org Link to comment Share on other sites More sharing options...
shn7 Posted June 29, 2008 Share Posted June 29, 2008 How many miles (road/track) has the gearbox done? I reckon it's clutch/crb replaacement time and the gearbox is fine. You could give R&R a call and talk about it with them. Very helpful people. If you decide to let R&R look at it why not make anappointment for them to do it while you wait. I watched my gearbox completely stripped, cleaned, new synchros and rebuilt in 2 hours. Fascinating to watch an expert at work. Steve. Sussex (West) AR Not forgetting Percy the Polar Bear Link to comment Share on other sites More sharing options...
Shad Posted June 29, 2008 Author Share Posted June 29, 2008 It's covered just over 30k miles, I've done about 500 miles of track use this year and umpteen more 'spirited' road miles. I am doing about 1000 miles a month with the car at the moment though, 8k since November Anyway I will speak to R&R tomorrow and see what they think. Quite happy to wait around while work is done, it's a long trip for me so would be the sensible option Cheers Simon niknak.org Link to comment Share on other sites More sharing options...
Shad Posted July 12, 2008 Author Share Posted July 12, 2008 Phil had an idea what the problem was when I described it over the phone and said they would happily take a look. Dropped it off yesterday and sure enough, it required a new main shaft, second gear and a few syncro rings and bearings. They turned it around inside the day which is absolutely fantastic, and it was cheaper than I expected too, so another very satisfied Road & Race customer here! Just got to put it all back together now... Simon niknak.org Link to comment Share on other sites More sharing options...
Mick Day Posted July 12, 2008 Share Posted July 12, 2008 it required a new main shaft, second gear and a few syncro rings and bearings. Similar problem to mine then. Glad you've got it fixed. Now you've taken the engine out once it's not so daunting a task next time. 😬 Link to comment Share on other sites More sharing options...
Shad Posted July 12, 2008 Author Share Posted July 12, 2008 Indeed, always a silver lining Just goes to show, get your gearbox serviced. If I'd have had it done when I bought the car it would have been ok. The piece that failed is some kind of spacer ring, really cheap and something they replace as part of a service. When it fails 2nd and a hub thing (technical term) start to get too hot and weld themselves to the mainshaft! Regular service every winter from now I think Simon niknak.org Link to comment Share on other sites More sharing options...
Shad Posted August 27, 2008 Author Share Posted August 27, 2008 Just got around to cleaning the broken bits that I salvaged from the gearbox. The damage is really clear to see, a surprising amount of material has been worn away and there's quite a bit of discolouration on some of the surfaces so I guess it was pretty hot in there... Knackered hub thingy 2nd gear, quite a bit of wear on this side Other side of 2nd Very badly worn face They two bits together do make quite a nice desk tidy though Simon niknak.org Link to comment Share on other sites More sharing options...
Jason Plato Posted August 28, 2008 Share Posted August 28, 2008 what oil were you using ? here is C7 TOP Taffia rear gunner Link to comment Share on other sites More sharing options...
Mick Day Posted August 29, 2008 Share Posted August 29, 2008 They two bits together do make quite a nice desk tidy though I have an inlet & exhaust valve (bent of course) alongside other broken trophy items on my desk. Link to comment Share on other sites More sharing options...
Shad Posted August 29, 2008 Author Share Posted August 29, 2008 what oil were you using ? Redline MTL, which I'm now avoiding on the advice from R&R. Simon niknak.org Link to comment Share on other sites More sharing options...
Mick Day Posted August 31, 2008 Share Posted August 31, 2008 Redline MTL, which I'm now avoiding on the advice from R&R.Interesting - as MTL used to be the flavour of the month & recommended by R & R. My box was using Castrol when I had my big problem, but is now using MTL. MTL does result in a nice fluid shift though. So why is MTL verboten now? Link to comment Share on other sites More sharing options...
Shad Posted August 31, 2008 Author Share Posted August 31, 2008 I was using it too but they mentioned that there might be a problem with it. Some recently rebuilt gearboxes started having problems after only a few hundred miles while using MTL. Best speak to them for a fuller explanation! Simon niknak.org Link to comment Share on other sites More sharing options...
6speedmanual Posted August 31, 2008 Share Posted August 31, 2008 Redline MTL is a suitable oil for manual transmissions with synchromech. That is what it is specifically designed for. The recommendations here and elsewhere are based on the fact that it works and gives good gearshift quality. Any confusion which seems to have crept in is because (unconfirmed allegation) there seems to have been some batches of MTL which "may" have had GL5 additives blended in by mistake. The extra slippery GL5 stuff for high load applications is not good for synchro rings. They cannot "bite" through GL5 oils and therefore skid and then over time start to polish up. If a driver persists with the condition hoping it will bed-in it will only get worse. Once this has happened the synchros need replacing. If you put MTL in your gearbox and the synchros work then it's ok. If GL5 was in your 'box, you would know in just a few miles, even the first time up and down the 'box, if you had poor synchro performance. If you drain oil and fill with GL4 straight away there would be no damage done. If you had a race car and the first time you really got to use a freshly rebuilt 'box was at a race meeting, by the time you've done practice/quali the synchros could be goosed. I think R&R may be leaning to the side of caution and recommending alternative oils with which no such post-rebuild problems have been apparent to them. One such oil would be the Comma Caterham recommended manual transmission oil. On the very day I changed my gearbox oil to MTL I was in conversation about gearbox oils and heard of this issue. Consequently I was very careful to feel for any lack of synchro performance. I was fully prepared to dump the freshly filled oil at the slightest hint of a problem. As it turned out, I found no problem on the initial drive after the oil change nor in following days. I have now covered about 1200 miles since including hundreds of gearchanges on my Alpine blatting this summer and gearchange is really sweet. Key thing is the correct GL4 grade. Hope this helps... Peter 6SpeedManual *tongue*There's no such thing as too much BHP per Ton 😬 Link to comment Share on other sites More sharing options...
Shad Posted August 31, 2008 Author Share Posted August 31, 2008 Great post Peter R&R mentioned the polishing and advised being cautious and suggested I stick with the Comma stuff, which I have done. I'm happy with that for now. Simon niknak.org Link to comment Share on other sites More sharing options...
Mick Day Posted August 31, 2008 Share Posted August 31, 2008 Last rebuild was in early 2006 & I've been using MTL with no problems. I can only assume it has the correct GL4 additives. Link to comment Share on other sites More sharing options...
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