Either Transmission or Clutch failure - NEED HELP

Nissan 300ZX technical discussion forum: Maintenance, performance, installations, modifications, how-to's and troubleshooting.
Afrikaaner
Posts: 27
Joined: Fri Sep 25, 2009 3:39 am
Car: 1990 300zx NA

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so i was driving yesterday after having heard some strange noises (thought it might be a bearing going on the clutch) that i couldn't reproduce, but occurred now and again as i would be on the clutch and put it into first gear. what happened was i was my clutch pedal just suddenly felt really weird - the first 3/4 felt very light, and the last 1/4 felt like it was gritty and very firm. and when i pressed it, it didn't want to come out of gear unless i shifted it using rev matching. so i limped to my friend's house in third gear, and went to test drive it to see if he couldn't pinpoint it. however after i parked, the clutch felt and worked fine - even with the engine running (idle). so he went out, and felt how fubar it was, and when we came to a stop at one point and was not in gear, he was unable to get it back in without fighting with the clutch and shifter for a while. after he got it back in gear (again, i think it was in third) we went home and were unsure what exactly was giving us issues. so i drove it home (third the whole way lol) and at one light, when i was holding the clutch down, it started to stall. so i brought it out of gear, and (prayed) put it back into third, and this time i was able to keep it in gear with the clutch depressed without it stalling. then when i parked again at my house, everything seemed to be working fine. however, i noticed when i had the car on, and i would have the clutch pressed, i could move the shifter around fine, but the transmission made rather loud whining noises. this is making me think maybe its the syncros or something that are dying/dead? i know i also had trouble recently in the cold weather getting into second gear before the transmission warmed up (would not let me in unless i double clutched or let engine drop to idle).

soo, any great ideas? the problem im having now is that it seems both the transmission and the clutch have given out (the clutch not disengaging at the light on my way home and the noises from the transmission while parked). someone recommended i try bleeding the clutch lines, but im really quite skeptical of that, although im certainly no master when it comes to cars....

anyway, thanks in advance for any advice


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Ace2cool
Posts: 11650
Joined: Sun Apr 20, 2008 5:21 pm
Car: 1991 Nissan 300ZX TT
1966 Datsun Fairlady 1600
2005 Suzuki GSX-R 600
1974 Honda CB550 Four
2009 Ford F150 Lariat
Location: Murfreesboro, TN

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Honestly, take your friend's advice. Bleeding the clutch is free. Everything I'm about to suggest costs money. There are 2 bleed points for the clutch: one under the pass side hood behind the p/s reservoir and one at the slave cylinder. If that doesn't fix it (which it may), then it might be master cylinder failing, may be slave.

As far as being hard to go into 2nd, the synchros in 2nd and 4th are known to go bad.

At this point, just try bleeding the clutch and let us know what that does. The intermittent working might be air in the lines. After we fix that, we can narrow down more problems.

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smkn92Z32
Posts: 61
Joined: Fri Jul 25, 2008 10:28 am
Car: 1992 300ZX n/a, 1969 Chevelle Malibu 350

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pretty much the same thing happened to me while driving my girlfriends old bmw 325 (also hydro clutch coming off the brakes) and it was a bad slave cylinder. see if you have a leak in your brake system (at the calipers, check in your wheels, lines, master cylinder, brake fluid reservoir) or maybe right out the slave cylinder on your transmission. if youve ever had low brake fluid this is why. if this is the problem its a good idea to swap out the master and slave at the same time. one bad unit will kill off the good one prematurely.

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Zwicked
Posts: 3133
Joined: Mon May 14, 2007 6:19 am
Car: 1990 300 ZX tt, 1990 240SX

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It could be a few things. If it isn't leaking any fluid under the right side of the trans, then it's likely not the slave.Get under it and have someone depress the clutch pedal and watch the throwout arm to see if it travels full stroke. If it barely moves then it's likely the master cylinder. If it does move then it's probably your clutch pressure plate or throwout bearing, which in any event is a trans pull to replace it. After a clutch gets old, often the springs become weak or even break on the PP.

Afrikaaner
Posts: 27
Joined: Fri Sep 25, 2009 3:39 am
Car: 1990 300zx NA

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so i bled the clutch (did nothing, although the fluid was like coffee), and the problem has gotta be my clutch (cant shift unless i rev match or at stops i turn the car off, drop into first, then start it in gear....). so im gonna be dropping the transmission on monday, and i'm thinking of doing a lighter flywheel, a z1 solid driveshaft, new clutch/pressure plate (maybe master cylinder depending on what's busted), bearings, and a transmission rebuild (i know second gear's synchro and 4th is going) while im in there. im going to be doing this where i work and storing my car there. any advice on parts i should take a look at? or advice on what i should look out for? thanks!


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