Lazeum Posted May 14, 2012 Share Posted May 14, 2012 (edited) Car just got back on the road after 2 years of maintenance (full suspension/steering & engine rebuild) I have change fluid in my transmission (280zx trans) in the process right before the first drive. Front of the car was lift off to get access to the filler hole during the process. I was able to pour nearly 2,5 liters of fluid before it started to get out from the hole (due to the fact that car was not sitting flat). Service manual is mentioning 1,5L, so I have over filled the trans by 1L (40% more, that a lot!) Right now, I can see the transmission leaking thru the hole near the clutch (by the smell of the oil, I know it is not coming from the engine - not yet broken in). It is also not coming from the exterior of the trans (speedo cable or reverse switch for instance). I have stuck pieces of paper towel everywhere around the potential leakage areas to make sure fluid was not coming from anywhere else..<BR style="mso-special-character: line-break"><BR style="mso-special-character: line-break"> It was not leaking a week before the change. Fluid volume that came out from the transmission was a little over 1L, not much more – closer to the spec but on the low side. Before I teardown everything to replace the front transmission seal (and the rear while I’m at it, which is not leaking), I was wondering if it isn’t normal to have fluid coming off my trans since it’s obviously overfilled? Should I just leave it the way it is until it stops leaking? Should I drain the excess of fluid? (I can open the plug & let the car sit for some time until level becomes good again) What would you advice? Edited May 14, 2012 by Lazeum Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 14, 2012 Share Posted May 14, 2012 Why not drain the fluid, and refill with the correct amount and see if the problem goes away? Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted May 14, 2012 Share Posted May 14, 2012 Yeah just drain and refill. Catch all the fluid with a clean pan and since its fresh put the proper amount back in. Quote Link to comment Share on other sites More sharing options...
Lazeum Posted May 14, 2012 Author Share Posted May 14, 2012 Sounds like something easy to do, then. Wouldn't you be concerned knowing seals are not effective? I mean I see no reason why it should leak even if the trans is overfilled. Maybe, it is normal, I haven't spend too much time on the transmission during the rebuild (which is a shame, it was easy to do while the engine was next to the car ) Quote Link to comment Share on other sites More sharing options...
NewZed Posted May 14, 2012 Share Posted May 14, 2012 Pretty sure that the "proper level" is up to the bottom of the fill hole with the car level. You could just remove the fill plug, level the car, let the excess drain out, and put the plug back in. Then see if it still leaks. How do you know where the fluid is coming from if the transmission is mounted to the engine? How can you see the hole that you described? Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 14, 2012 Share Posted May 14, 2012 Wouldn't you be concerned knowing seals are not effective? I mean I see no reason why it should leak even if the trans is overfilled.) I just checked on the spare tranny in my basement and the fill plug is below the input shaft meaning that the only fluid that should come up against the front seal is splashed there. In other words, it's not designed to have the fluid constantly pressing against it. Quote Link to comment Share on other sites More sharing options...
Lazeum Posted May 14, 2012 Author Share Posted May 14, 2012 Pretty sure that the "proper level" is up to the bottom of the fill hole with the car level. You could just remove the fill plug, level the car, let the excess drain out, and put the plug back in. Then see if it still leaks. How do you know where the fluid is coming from if the transmission is mounted to the engine? How can you see the hole that you described? The solution you described is the way to go. Luckily fill plug & drain plug ae very easy to handle. I'll give a try and get the fluid back. Regarding the source, the tranny fluid is having a very different smell than motor oil. So by sticking my nose next to the fluid, I can easily tell where it comes from. The hole I'm talking about is cast into the clutch housing. It is actually a notch against the plate that cover the engine block. I think its purpose is exactly what I'm experiencing . I have no picture unfortunately. Quote Link to comment Share on other sites More sharing options...
Lazeum Posted May 14, 2012 Author Share Posted May 14, 2012 I just checked on the spare tranny in my basement and the fill plug is below the input shaft meaning that the only fluid that should come up against the front seal is splashed there. In other words, it's not designed to have the fluid constantly pressing against it. Thanks! that's exactly the kind of info I need Quote Link to comment Share on other sites More sharing options...
NewZed Posted May 14, 2012 Share Posted May 14, 2012 The hole I'm talking about is cast into the clutch housing. It is actually a notch against the plate that cover the engine block. I think its purpose is exactly what I'm experiencing . I get it, I've done the same thing. Gear oil smells better than used motor oil. Uuhhmm... Another spot that might leak due to seeing a high oil level would be the front cover bolt holes. The holes are tapped through to the inside of the cover and can pass fluid along the threads. The top ones, that might only see a splash or two due to braking and turning over time, might be seeing a steady oil supply now. The FSM recommends sealing the threads upon assembly but I'll bet that a lot of people don't. The right oil level might get you back to normal, but it might take a little while for everything to drain out. Another spot, but which would probably leak all of the time (one of mine did), is the clutch pivot ball bolt. It's also tapped through the cover. Quote Link to comment Share on other sites More sharing options...
Lazeum Posted May 15, 2012 Author Share Posted May 15, 2012 I did not know about those points, that's good info as well. I've got special compound to seal threads against hydrocarbure since I've redone my fuel system with new pump. That's something I'll take into consideration if I take care of the seal (in a while, I hope!) Quote Link to comment Share on other sites More sharing options...
Lazeum Posted May 19, 2012 Author Share Posted May 19, 2012 (edited) I've taken care of the fluid level yesterday. I went for a 40mi test drive afterwards. No more leak under the car after one full night sitting in the garage I took many tools in my work garage, I will however disassemble the gearbox anyway to clean the mess and seal everything for good to avoid having an oily clutch in the future. Everything is good now. Car is awesome, I missed driving the Z. Thanks to all for your help! Edited May 19, 2012 by Lazeum Quote Link to comment Share on other sites More sharing options...
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