Onion Posted March 5, 2014 Share Posted March 5, 2014 This has happened twice now. I brushed the first time off as a fluke, but now that it's happened three times, its a recurring problem. Its a 5 speed from a 1978 Z that I bought off a member here. He estimated it to have about 100,000 miles. Had it installed by a good shop since I can't do that much labor at my apartment complex. It drove fine for about a month. Basically when I shift from a gear and I don't do it very gently, it gets jammed in between two gears. I can sometimes push it back into the gear it came from. It doesn't seem to make a difference based on what gear I'm coming from. The shifter gets jammed and I have to wiggle it around and shake it until it breaks free and I can then drive normally again. It seems to be harder and harder to break it free each time it happens. Any ideas? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 5, 2014 Share Posted March 5, 2014 Something similar happened to my car on the track, and has happened to my friends car twice on the street. Ours got REALLY locked into 5th and another gear at the same time. On hers, the trans had to be pulled and the shift pin moved by hand. Our solution was to shim up the detent springs. It happened so rarely, I can't tell you for sure whether that worked. Quote Link to comment Share on other sites More sharing options...
duragg Posted March 5, 2014 Share Posted March 5, 2014 How's the condition of the bushings at the shifter area? Quote Link to comment Share on other sites More sharing options...
Onion Posted March 5, 2014 Author Share Posted March 5, 2014 How's the condition of the bushings at the shifter area? Haven't looked at them but they're probably pretty bad. The shifter is sloppy at best. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 5, 2014 Share Posted March 5, 2014 FWIW, the shifter bushings on the 2 ZX NA transmissions with this issue were fine. Both of us had replaced with factory bushings. Quote Link to comment Share on other sites More sharing options...
Onion Posted March 5, 2014 Author Share Posted March 5, 2014 I'll start to look into the current transmission and try to isolate the problem. I have a second 5 speed with a bad shaft (can't remember if it's input or output). Do you guys think I could salvage parts from that one and just put them on the working transmission? Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 5, 2014 Share Posted March 5, 2014 Aren't the interlock balls in the adapter plate what allows only one gear selection at a time? Banging gears, bad lubrication and general use/abuse wears the balls and their locations, apparently. It's one of the things to check and replace when rebuilding a transmission, I think, although I don't know that it's described in the FSM. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 5, 2014 Share Posted March 5, 2014 Aren't the interlock balls in the adapter plate what allows only one gear selection at a time? Banging gears, bad lubrication and general use/abuse wears the balls and their locations, apparently. It's one of the things to check and replace when rebuilding a transmission, I think, although I don't know that it's described in the FSM. That's what we shimmed up. We put a stack of washers on top of the spring. I don't recall a lot of wear on the shift rails, but this was ~15 years ago. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 5, 2014 Share Posted March 5, 2014 Those would be the check balls, I believe. For neutral location? I think I figured out at one time that the interlock balls ride on the rods and get pushed in to a location on the adapter plate when the rod moves, locking out the other rod from movement, since there's only room for one ball. Or something like that. It was a puzzle. Anyway, the problem is probably in that area. Could just be that the fluid level is low, or old and gummy, or both. Maybe a fluid change and top-up would help. Quote Link to comment Share on other sites More sharing options...
Onion Posted March 7, 2014 Author Share Posted March 7, 2014 Fluid is brand new, the transmission sat dry for about 4 years and was filled a bit over a month ago when I put it in the car. I haven't seen any leaks under the car but I'll crack her open to make sure that it's still well filled. That diagram is incredibly helpful, I was looking for something like that to tear apart my old transmission and replace anything worn and broken. Thanks a lot guys. Quote Link to comment Share on other sites More sharing options...
Onion Posted March 28, 2014 Author Share Posted March 28, 2014 (edited) Update, more info about the problem. Will not jam with engine off and clutch in or clutch out. Will not jam on idle. ONLY jams when moving. Jams harder and more often at higher RPMs. Shifting is smooth with clutch in and car stationary and with the car off. Shifting is notchy when car is moving. At low speeds (when the exhaust is quiet), going from first to second is notchy and I hear a sort of "thunk" noise from outside the car as soon as it hits the notch. It then gets past the notch and goes into second. So, syncros? Spoke to some guys in the chat and I tested the transmission with the car off and they said it was air in the lines. But now that I know it only does it when the car is moving, it's leading me to believe otherwise. Edited March 28, 2014 by Onion Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 28, 2014 Share Posted March 28, 2014 Basically when I shift from a gear and I don't do it very gently, it gets jammed in between two gears. I can sometimes push it back into the gear it came from. It doesn't seem to make a difference based on what gear I'm coming from. The shifter gets jammed and I have to wiggle it around and shake it until it breaks free and I can then drive normally again. It seems to be harder and harder to break it free each time it happens. Any ideas? Which gears? All of them? 1-2, 2-3, 3-4, 4-5? And are you really banging gears like you're trying to break something, or just shifting fast? The synchro gears just match gear speeds, there's not really much to get stuck there. Sounds more like you've damaged the shift rods, balls and adapter plate with the gear-banging. The balls aren't dropping back to their neutral locations. If you take it apart to look at the synchros, you'll see those parts anyway. But I'm just guessing. duragg knows these transmission details by heart. Give better details and someone might know for sure. Quote Link to comment Share on other sites More sharing options...
Onion Posted March 28, 2014 Author Share Posted March 28, 2014 Which gears? All of them? 1-2, 2-3, 3-4, 4-5? And are you really banging gears like you're trying to break something, or just shifting fast? The synchro gears just match gear speeds, there's not really much to get stuck there. Sounds more like you've damaged the shift rods, balls and adapter plate with the gear-banging. The balls aren't dropping back to their neutral locations. If you take it apart to look at the synchros, you'll see those parts anyway. But I'm just guessing. duragg knows these transmission details by heart. Give better details and someone might know for sure. I'm shifting fast, but not fast like I'm racing. If I shift casually its notchy, if its fast they get stuck. I've never banged gears with this transmission, I've only had it for about a month. I bought it from a member here who promised it worked great. I've only had the issue happen going from 1-2 and 3-4. Looks like its time to buy a third transmission to put in the car so I can keep driving while I fix the other one. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 28, 2014 Share Posted March 28, 2014 You might try the shifter bushings. They're cheap and may help some. I'd also give good fluid a try. Your situation is sounding less and less like what happened to me and my friend. Our transmissions shifted fine, but on 3 separate occasions they actually locked the rear tires solid, because the trans fully engaged 2 gears at once. Quote Link to comment Share on other sites More sharing options...
Onion Posted March 28, 2014 Author Share Posted March 28, 2014 (edited) You might try the shifter bushings. They're cheap and may help some. I'd also give good fluid a try. Your situation is sounding less and less like what happened to me and my friend. Our transmissions shifted fine, but on 3 separate occasions they actually locked the rear tires solid, because the trans fully engaged 2 gears at once. Fluid is brand new but its whatever the shop put in it. I'll read up on trans fluids and see what you guys recommend. Shifter bushing is ordered. The shifter has quite a bit of play, so even if it doesn't fix the jam problem, it'll help with the play problem. Yeah, we're having different issues. I've never had it jammed in gear, it's always been jammed between gears. Edited March 28, 2014 by Onion Quote Link to comment Share on other sites More sharing options...
Zero83 Posted March 29, 2014 Share Posted March 29, 2014 hm, idk man, let me do some looking around. Quote Link to comment Share on other sites More sharing options...
Zero83 Posted March 29, 2014 Share Posted March 29, 2014 give this a read, http://www.zcar.com/forum/10-70-83-tech-discussion-forum/81389-what-problem-my-gearbox-280zx-5-speed.html Quote Link to comment Share on other sites More sharing options...
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