stevie_b Posted July 14, 2015 Share Posted July 14, 2015 I have a W58 5-speed manual gearbox in my supra. Changing from 1st to 2nd, especially when cold, I have to push the clutch pedal down really hard to get a smooth change, almost like I'm trying to push it into the engine bay. I've changed the gearbox oil 2 weeks ago. It's improved the gerar changes a bit, but I'm still not happy with it. If I don't really push on the pedal from 1st to 2nd, I often get a clunk which I can feel through the gear lever. I'm pretty sure my floor mat hasn't rucked up under the clutch pedal and stopping the clutch from disengaging properly. It's been suggested that the pressure plates might be worn out, or the clutch might need bleeding. Any advice gratefully received. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted July 14, 2015 Share Posted July 14, 2015 Sounds like it may need bleeding or if that doesn't fix it, a new clutch. Assuming the master and slave cylinders are OK. Any sign of leaking? You need to look up above the pedal to see a master cylinder leak. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted September 10, 2015 Author Share Posted September 10, 2015 No visible leaks from either master or slave cylinder, and the fluid level in the master's reservoir is constant. I'll try changing the clutch fluid this weekend to see if that helps, although the fluid's colour looks OK. Some more info about my symptoms: Only when I change gear from 1st to 2nd, when the lever is moving from neutral to 2nd, there's a grind/rumble/vibration. You can hear it (I doubt it's loud enough to record on a phone though), and feel it through the gear lever. It doesn't happen if I let the revs die right down between 1st and 2nd gear. It doesn't happen for any other gear change, only 1st to 2nd. Does anyone recognise those symptoms? I'll let you know if the clutch fluid change improves it. If not, I don't know whether to get the clutch changed, or get the gearbox refurbed. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 10, 2015 Share Posted September 10, 2015 Sounds like the gearbox has tired synchos on 2nd gear. Been doing any "enthusiastic" drag race type changes previously? Changing the clutch fluid is a waste of time and money, save it for another gearbox, or a rebuild. The reason it's worst when cold is the more viscous oil puts more of a strain on the worn synchros. The thick oil drags on the gears and makes matching their speeds harder. Classic signs of synchros wearing out. There's a slight chance it's the clutch itself dragging, but I would expect that would manifest itself in difficulties in other gears, especially going into reverse. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted September 10, 2015 Author Share Posted September 10, 2015 Thanks Chris. Reverse is easy to get into, as are all the other gears. I don't do enthusiastic driving or gear changes: street, dragstrip or circuit. I get a nosebleed if I take my car above 4000rpm. I kid you not, buses out-accelerate me in my Supra. Can anyone recommend a gearbox rebuilder? These guys are close but I have no recommendations: http://www.tadleytransmissions.co.uk/gearbox-repairers/default.asp Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 10, 2015 Share Posted September 10, 2015 Manual gearbox parts are historically *VERY* expensive, but finding a better used box is a lottery. If it's rebuilt it would be madness not to do all the synchros and synchro hubs and all the bearings £££££££'s Quote Link to comment Share on other sites More sharing options...
j-a-y Posted October 17, 2015 Share Posted October 17, 2015 Hi stevie I was wondering did you sort this problem out as I had a similar problem with tough gear change over a year ago, some how I broke the main hub bearing! hears a picture. Quote Link to comment Share on other sites More sharing options...
Scott Posted October 17, 2015 Share Posted October 17, 2015 Have you tried adjusting the clutch rod behind the pedal? Perhaps it just needs a mm more travel to disengage fully. I had a similar issue years back with my MR2. Garage fitted new clutch but the biting point was right down the bottom of the pedal, took me years to figure out it could be adjusted behind the pedal Quote Link to comment Share on other sites More sharing options...
stevie_b Posted October 17, 2015 Author Share Posted October 17, 2015 I haven't fixed it yet. I've been speaking with a transmission specialist who'll take the gearbox apart and see what (if anything) needs replacing. From advice on here and from the gearbox guy, I strongly suspect it's a worn synchro. I haven't tried adjusting the clutch rod. Could this still be the cause if the gearchange is fine once the box has warmed up, and that it only happens on a specific gear change? The reason I ask is that I don't want to fiddle with other settings, and compound the problem. Quote Link to comment Share on other sites More sharing options...
Scott Posted October 17, 2015 Share Posted October 17, 2015 Symptoms are very similar to what I had in the MR2. 1st & 2nd crunchy when cold, no bother when warm. I will add that regardless of gear the clutch would always engage right down the bottom of the pedal. I had to adjust the rod to move the travel up a little. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted October 18, 2015 Author Share Posted October 18, 2015 ...2nd crunchy when cold, no bother when warm. I will add that regardless of gear the clutch would always engage right down the bottom of the pedal. I had to adjust the rod to move the travel up a little. Interesting, these are my symptoms. When you say the clutch engaged at the bottom of the pedal travel, do you mean the biting point was right at the bottom? Quote Link to comment Share on other sites More sharing options...
Scott Posted October 18, 2015 Share Posted October 18, 2015 Interesting, these are my symptoms. When you say the clutch engaged at the bottom of the pedal travel, do you mean the biting point was right at the bottom? Indeed. Generally when a clutch is on the way out the bite is at the top. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted October 19, 2015 Author Share Posted October 19, 2015 For my future reference as much as anything, I searched on here about the adjstable clutch pedal and found this (post 17 in particular): http://www.mkivsupra.net/vbb/showthread.php?44729-Supra-Clutches-can-you-alter-the-biting-point/page2 I've tested the clutch on my car, and it bites roughly in the middle of the pedal travel. Quote Link to comment Share on other sites More sharing options...
Scott Posted October 19, 2015 Share Posted October 19, 2015 Sounds spot on so doubt it needs adjusted then. Almost a cheap fix lol. Quote Link to comment Share on other sites More sharing options...
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