Flak280z Posted January 19 Share Posted January 19 (edited) Hello all, I have a 78 280z that I just swapped an 82 280zx 5 speed into along with a 3.9 r200. Also replaced clutch stuff (pp, disk, throw-out). Hearing a grinding now in neutral and in gear. It goes away when clutch is pushed in. Noise does not go away when slave cylinder is disconnected. Does this sound more like a throw-out bearing or the input shaft bearing? Any tests I can do? I swapped this tranny in to replace a bad 2nd gear synchro on my stock 5 speed, so I'm hoping it's not the input shaft bearing. Edited January 19 by Flak280z more experimenting done Quote Link to comment Share on other sites More sharing options...
bunkhouse Posted January 19 Share Posted January 19 If the noise goes away when the clutch pedal is pushed down, the noise is coming from the transmission. The disengaged clutch stops the transmission from spinning. Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 19 Share Posted January 19 "Grinding" is not very specific. Can you add details? Have you driven it? Is it the same in every gear? 71B's are known for destroying the adapter plate bearings. Did you find any metal on the drain plug magnet? If you've been driving it you might drain the fluid and see how it looks. Might also be worthwhile to lift the car and get underneath with the engine running to see if you can locate the noise. Replacing the main and countershaft bearings is not very difficult. You only have to split the cases and pull the bearings off of the ends of the shafts. The adapter plate bearings are more difficult. 2 Quote Link to comment Share on other sites More sharing options...
Flak280z Posted January 20 Author Share Posted January 20 Yes, noise goes away with clutch pedal in. Is also present in neutral, which leads me to the input shaft. I just installed this tranny as a swap, it had been in someone's garage drained of fluid for awhile. Have mt-90 in it, and drove it probably 20 miles to listen to the whirring/grinding. It's coming from towards the bellhousing area, which also leads me to believe it's the input shaft bearing. NewZed, by "Main" bearing, do you mean input shaft? The noise seems to go away in 4th, which, by searching through forum posts, seems to lead me back to the input shaft bearing. All this info makes me pretty dead set on the input shaft, just seeing if there was any other insight. Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 20 Share Posted January 20 4th gear doesn't use the countershaft, it's direct drive. That's a good clue. Sounds more like the countershaft bearing. Looks like you'll need to split the cases, so you might as well do the mainshaft/input shaft bearing also. It's not a super-finesse job. Just needs some ingenuity. It's fun. Part of Z ownership. Here's a good illustration of the parts you'll be looking at. I'm sure that there are "how-to" videos out there somewhere. You can get a factory service manual on the internet that shows how to take it apart. Good luck. https://www.zhome.com/ZCMnL/tech/240SX5spd/Transmission2.htm 2 Quote Link to comment Share on other sites More sharing options...
Flak280z Posted January 21 Author Share Posted January 21 Thanks for the help! I'll just replace both. I do have a FSM, but I sometimes get confused with the wording. Downfalls of this being my first project car. Appreciate you guys and the help you give. Quote Link to comment Share on other sites More sharing options...
Flak280z Posted January 21 Author Share Posted January 21 (edited) I have it all apart. To pull the countershaft and main bearings, do I remove the rods on the right? Edited January 21 by Flak280z Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 22 Share Posted January 22 No, you just pull the bearings off of the front of their shafts. The countershaft bearing is pretty tight to the gear and takes some trickery. The mainshaft bearing needs a puller with long arms. You can push the rods back to get more room. The transmission will have multiple gears engaged but it won't matter. When you reinstall the front case put it in a single gear (one rod moved) to avoid locking up the transmission by accident. Here's a decent video about the countershaft bearing, different tranmsision but same concepts. He did the same thing I did, clamping a two jaw puller in to the gap, otherwise the jaws pop off. The mainshaft is a more normal operation but the length of the shaft has to be managed. It takes some work. If you have friends that have pulled bearings or gears it might be worhtwhile to get some more ideas and tools on-hand. Notice the odd combination. Go to 4:00 if it doesn't start there. 1 1 Quote Link to comment Share on other sites More sharing options...
Flak280z Posted January 26 Author Share Posted January 26 (edited) Good News, replaced both the front main-shaft and front counter-shaft bearings which solved my grinding problems! So, to recap the project, I am finished installing a 82 280zx transmission, r200 3.9 rear diff, and a new clutch disk and pp. Bad news is that I now have a shudder and a howl noise. The shudder happens when accelerating from a stop. It feels like the diff is grinding/not catching. It seems like the problem does not occur when I keep the revs high when accelerating from a stop. Does not happen in any gear besides 1st. It might just be a user error with me not being used to the new clutch/tranny. I've read that adding some friction modifier helps with this issue in LSD's, but IK this is an open diff. Could that help here? The howling noise I'm pretty sure is transmission related, as it only occurs in 1-3rd gears. It does seem to follow the rpms and go up when accelerating, but disappears in 4th. It is not that loud to begin with though. Edited January 26 by Flak280z spelling 1 Quote Link to comment Share on other sites More sharing options...
bunkhouse Posted January 27 Share Posted January 27 Any possibility of oil getting oil on the new clutch disc or pressure plate? I've seen old clutches shudder when they had oil on them. Quote Link to comment Share on other sites More sharing options...
Flak280z Posted January 27 Author Share Posted January 27 I just put the transmission back in today, empty, and filled it with 75% swepco/25% atf. No chance of any on clutch. I have a feeling it's just me. Does the closer ratio of the zx tranny along with the higher 3.9 diff need more rpm's to get going? It feels like the engine bogs down, and the rear diff grinds/shudders. Quote Link to comment Share on other sites More sharing options...
Flak280z Posted January 27 Author Share Posted January 27 Well, after more testing, it seems to be a user error. Was able to drive for a good hour today without and bucking/shudders. I think it's a combination of a new clutch and upgraded transmission/rear end that I have to get used to. The car seems to like higher rpms when starting from a stop, and a different clutch engagement that what it was before. Car is much more fun with the new parts. Not a fast car, but a fun one. 2 Quote Link to comment Share on other sites More sharing options...
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