TrumpetRhapsody Posted June 3, 2008 Share Posted June 3, 2008 So I'm gearing up to try to drive the Z 1.5 hours from our shop to my new house. I've got almost all of the bases covered, but I'm concerned about my tranny... It's supposedly an "A" style 5spd out of a 76 280z, but 5th doesn't work for me. I can hold it in 5th and it'll sometimes work, other times it'll grind and pop out. My concern and reason for this thread is some grinding I have going on. It only happens when decelerating. Flat coasting is usually fine, and acceleration is fine. I had a passenger stick his head out, and it sounds like its coming from the tranny, so I don't THINK it's the diff. Does it sound like the symptoms of a bad throwout bearing, or something more serious inside the tranny? Is it something I should take care of before trying to drive it home, or do you think it'll be ok temporarily? I just had the tranny out to replace a bad front cover gasket, so I'm not too keen on dropping it again if I'm not sure of the problem. Ideas, suggestions? Quote Link to comment Share on other sites More sharing options...
Dayz Posted June 3, 2008 Share Posted June 3, 2008 I am sure tranny guru's can answer on the exact symptoms, but I'd think you need to rebuild it. Your counter shaft bearing might be dying if I am not mistaken. Temporarily, yes it would be OK to drive 1.5 hour in fourth...I would do it. In the short/long run you will have to find another one or rebuild it. Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted June 3, 2008 Author Share Posted June 3, 2008 Thanks, thats a start. The whole 5th gear thing sucks and is inconvenient, but I guess it gives me the opportunity to see about playing around with different gearing stuff. I've read some about using truck gearing etc... Anywho the main concern is the grinding for now. I don't have much choice, i'll probably end up trying to get it back here, but I wanted to get a few opinions too. Quote Link to comment Share on other sites More sharing options...
turboboost Posted June 3, 2008 Share Posted June 3, 2008 It keeps you in the powerband at least. Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted June 3, 2008 Author Share Posted June 3, 2008 Haha yeah no kidding. I was at about 3k going an estimated 50mph (no speedo yet). Quote Link to comment Share on other sites More sharing options...
woldson Posted June 4, 2008 Share Posted June 4, 2008 Pull the bottom plug, I believe it is magnatized and check for "chunks". It will give you a better idea how bad things might be. There is some kind of "keeper" in the synco mesh?? that keeps a gear engaged under pressure and its problaly just worn out in fifth gear. I COULD BE WRONG HERE!! I've been told that you should never leave your hand on the shifter while in gear due to ware on the keepers. Also not to pull the car out of gear while coasting. The long range effects are "popping" out of gear. I shift with out the clutch all the time, and I do leave my hand on the shifter in certian gears. (shifting w/o clutch is DD not power shifting) Personally seems like she'll get you there just take it easy and maby diengage gear under deacceleation. Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted June 4, 2008 Author Share Posted June 4, 2008 Good to know. I don't believe there are any chunks. I tipped the tranny over and dumped all the fluid out the fill plug before taking off the front cover, and there were no shavings or anything. I suppose if I have it apart again I'll check the bottom plug if it's magnetized. Interesting information. I'll try to keep that in mind. Keeping my hand off the shifter could take some training, lol. I'll just have to try and take it easy I guess. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted June 4, 2008 Share Posted June 4, 2008 I thought that transmission used a ball and spring inserted into the center section from the outside of the trans to keep it in gear. If this is the case, the spring could be weak. This would cause it to pop out of gear. Evan Quote Link to comment Share on other sites More sharing options...
Nigel Posted June 4, 2008 Share Posted June 4, 2008 I'm betting the big mainshaft nut has backed off and is allowing some fore/aft movement of 5th gear on shaft. Consequently, you can't move the selector far enough to actually engage the gear properly to begin with, and when you decellerate, the helical cut gears push the gear on the mainshaft back and out of engagement. This is going by memory of the 5th gear assembly. I might have a couple of minutes after work to check a transmission I have apart to see if what I said is true. Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted June 4, 2008 Author Share Posted June 4, 2008 Hmm interesting... but would the grinding happen in all gears? Quote Link to comment Share on other sites More sharing options...
woldson Posted June 5, 2008 Share Posted June 5, 2008 Even seems to be correct. Studing this abit there is a ball, spring loaded, that sits against a shift fork that keeps the gear engaged. From what I have found out so far is that the spring can break, be soft (because of age), and form a grove in the shift fork. Will inquire more if you need. Quote Link to comment Share on other sites More sharing options...
Nigel Posted June 5, 2008 Share Posted June 5, 2008 Hmm interesting... but would the grinding happen in all gears? Not necessarily... That nut only keeps 1/2 gears and rev/5 "tight". The 1/2 gears are also kept tight by the interference fit of the mainshaft into the large bearing in the center plate. So, unless the mainshaft moves forward, there will be no slop in the 1/2 gears, even if the mainshaft nut comes loose. Here's a picture of the reverse and fifth gear assembly: Here's a picture of the first through fourth gear assembly (1st is the gear furthest to the right): Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted June 5, 2008 Author Share Posted June 5, 2008 Mmk well thanks for all the info guys, that'll be helpful. I'll drive it back for now, and tear it apart when I get it here. Fingers crossed! Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted June 8, 2008 Author Share Posted June 8, 2008 Alright well I took it for a 30+ minute drive today (which was awesome!). It grinds decelerating in 1st 2nd and 3rd, 4th is fine, and 5th is still touchy. I got it to stay in while accelerating, but it only dropped about 500rpms from what it was in 4th (about 2500 to 2000). Quote Link to comment Share on other sites More sharing options...
woldson Posted June 8, 2008 Share Posted June 8, 2008 Nigel's comments are FAR better than mine. He has the highest problablity of being correct!! Peace. Quote Link to comment Share on other sites More sharing options...
Trevor Posted June 9, 2008 Share Posted June 9, 2008 Hook a bungee cord between the glovebox and the gearshift to hold the trans in 5th. Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted June 9, 2008 Author Share Posted June 9, 2008 Lol that's what my dad said. Har har. I'll see if I can use it on the drive back today or tomorrow. It stayed in for awhile last time I drove it, it's just very finicky. Quote Link to comment Share on other sites More sharing options...
woldson Posted June 10, 2008 Share Posted June 10, 2008 It problay only comes out when you get off the accerator, correct? My 04 s10 dose that so I always just try to be nutral or on it slightly. So when you put it in 5th just put it to the floor and keep it there;) Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted June 10, 2008 Author Share Posted June 10, 2008 Lol Well I made it home in one piece, w00t! It grinds a bunch while driving, made me very nervous, lol. I tried 5th a few times and it grinds pretty good, and pops out on decel. Quote Link to comment Share on other sites More sharing options...
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