turbeau Posted September 30, 2009 Share Posted September 30, 2009 Stock 78 280Z, 5-speed. When in neutral or in gear and the clutch is engaged (pedal released), there is a whirring noise from the transmission. The noise increases in pitch with RPMs. The noise vanishes when the clutch pedal is depressed to the point where clutch disengagement happens. The noise does NOT cease by merely touching the clutch pedal. If the clutch pedal is pushed in, the engine is revved up, and the clutch is released (all the while, the transmission is in neutral) the sound will increase in pitch to match the revs once the clutch is engaged. I pasted this description from another thread because the poster described it so well, I have the exact same thing happening. I think it is the throwout bearing. My question is: is this noise just a noise, or should I open up the tranny and replace the bushings? Can I drive it for a while before the clutch stops working? Can anyone describe to me how the throwout bearing makes this noise? And if the clip comes off the release sleeve what happens? Quote Link to comment Share on other sites More sharing options...
Two80z4me Posted October 1, 2009 Share Posted October 1, 2009 mine does the same thing, never had a problem with the noise, but it does get noisy, so I got a glass pack. Its just a noise. Quote Link to comment Share on other sites More sharing options...
woldson Posted October 1, 2009 Share Posted October 1, 2009 Problem with throwouts going bad is they can explode, causing damage all over. It just may get worse untill you know there is a problem. Quote Link to comment Share on other sites More sharing options...
jasper Posted October 1, 2009 Share Posted October 1, 2009 The noise is most probably mainshaft bearings in the transmission. Whenever the clutch pedal is up, the input shaft is turning in the trans. Pushing the clutch pedal to the floor disengages the engine from the trans..shaft stops spinning. You might try gear oil additives, they may quiet it down a bit, but the bearings are still worn. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted October 23, 2009 Share Posted October 23, 2009 Sounds just like my transmission. It's been doing it ever since i got it but you never notice it unless you're outside the car. i've been meaning to change out the gear oil in it too, but FINDING the damn stuff is HARD (of course no one sells MT-90) Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted October 24, 2009 Share Posted October 24, 2009 is trans quiet in 4th gear?4th gear is straight through-1 to 1 ratio.if it gets quiet you have countershaft bearing problems.usually caused by trans fluid low because on speedo drive leak. Quote Link to comment Share on other sites More sharing options...
Nomake Wan Posted October 24, 2009 Share Posted October 24, 2009 Funny, I've got a '78 that does the same thing. I'm figuring Input Shaft Bearing, since as said before, the input shaft doesn't spin when the clutch is disengaged. The later post about fluid leaking from the speedo drive is interesting, since my speedo doesn't work either. Cable's fine, gauge's fine, and the cable keys in properly on both ends... but apparently the bit in the transmission doesn't spin since I get nothing on the gauge. I also get a clicking noise that's independent of engine speed but increases with vehicle speed, so that's probably a hint right there. Meh. The car runs and shifts for now. I'll probably end up tossing another trans in eventually to solve the problem. Almost not worth it to rebuild the one that's in it. Quote Link to comment Share on other sites More sharing options...
turbeau Posted October 24, 2009 Author Share Posted October 24, 2009 well the tranny broke while driving to JCCS. i looked under the car and the speed sensor was missing and all the gear oil had come out. now i am shopping for new 5 spd. any one have experience rebuilding a tranny? Quote Link to comment Share on other sites More sharing options...
turbeau Posted December 29, 2009 Author Share Posted December 29, 2009 i put a tranny in (junkyard 5sp), filled it up with gear oil, and still have the same noise. I reused the same clutch, pressure plate, fork, and throwout bearing. Noise sounds the same in all gears, maybe a little quieter in 4/5 but hard to tell because exhaust is loud. Tommorrow i will jack it up, check the fluid levels, and adjust the clutch slave cylinder. Could it be too tight/loose and cause something to rub? Quote Link to comment Share on other sites More sharing options...
NewZed Posted December 29, 2009 Share Posted December 29, 2009 I have a similar noise in my 76 with 4 speed. Based on the fact that it goes away when the transmission is under load I thought it might be the pilot bushing ni the end of the crankshaft. As I understand things, they can come loose and spin or they can get worn and give poor support for the end of the main shaft. Just another possibility, I have not fixed mine yet. Quote Link to comment Share on other sites More sharing options...
turbeau Posted December 30, 2009 Author Share Posted December 30, 2009 I talked to my local Z shop and they said it is a worn countershaft bearing. That means rebuild or replace because eventually it will fail. Rebuild was quoted at $1000, too much. thats half a 240z. Quote Link to comment Share on other sites More sharing options...
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