Need Help Identifying Transmission Clunking Noise.
 

So I’ve searched and searched countless threads trying to identify the noise my transmission is making. The sound happens when you release the clutch and it’s half way up. You can re-create the sound by pushing the clutch in and releasing it to its midpoint than back to the floor. It seems more pronounced when moving slowly almost like your lugging the engine. I’ve found several threads that start off promising but lead to nothing but dead ends and unfinished threads.

The clip I have attached at the bottom is exactly what mine is doing.

I thought U-joints so I’ve sourced two good driveshafts tried both and still does the same thing.
Ive already pulled my tranny and checked my flywheel, clutch, pilot bearing and throw out bearing. All which are new as of a couple months ago and seem fine. All bolts were installed and torqued properly.

The only thing I’ve found wrong so far is my input shaft seal somehow was damaged when I installed a new one a couple months ago. When I took the shaft cover off a bunch of gear oil spilled out. I had noticed a leak from the drain hole on the tranny but not enough t make me think I was low on gear oil but maybe that’s all it is? (Gear Lash or rollover?) Here’s a pic of the seal https://cimg4.ibsrv.net/gimg/www.mia...fbfbcd06ab.png

Any input would be appreciated. It would be cool to figure out since I don’t think anyone else has at least that I can find. I have a new seal on the way so after I install it I guess I’ll throw it back together make sure it’s filled and see if the problem goes away unless someone has a better idea and I do have acces to another tranny at the local pick and pull but would like to keep mine if possible.

Mine started making this sound after I installed a 5 speed, sprung pucked clutch, and 7lb flywheel. I never figured out what caused it, but always sort of assumed that I had done something to my driveshaft. Since you have swapped driveshafts and still have the noise, I'm going to assume that mine isn't the driveshaft. Now that I think about it, I wonder if it isn't somehow the combination of grabby sprung clutch and super light flywheel. I'm not sure what combo you are running though. When the clutch is slipped to take off, the springs are stretched. As the clutch and flywheel approach the same speed, the springs slowly return to their static position. If the pedal is depressed while the springs are still stretched, they will slap the clutch friction disc into the end of its travel. I wonder if the noise is the friction disc bouncing off of the travel limiter a few times.

Otherwise, I guess it's probably something with the transmission's internals or something I botched with my install. Either way, it's really annoying, and I can't afford to fix it. Once I graduate and have a decent job, I'll probably swap in a clutch that gets its grip from a stronger pressure plate rather than an aggressive friction surface along with a 6 speed and 3.63 gears. That should solve the problem.

Did you figure it out? Was it because of the seal? I have that exact same issue and it's getting worse. Wondering if I need a new transmission. Thanks

I ended up replacing the transmission and the problem was solved.

Ouch, this is the exact noise I have and I was hoping a transmission replacement wouldn't be the fix. Thanks for confirming that was the fix for this one.

This is the exact thing my miata appears to be doing. it makes the same sound. Did you do anything else other than replace the transmission to fix the noise? Was a clutch or anything done at the same time or was it definitely the transmission? Thanks for the help. Mine has been making this noise for a long time now.

I just found this and replaced with Mazda comp mounts. I'll report back once I get the car back together.


https://cimg6.ibsrv.net/gimg/www.mia...08119aad5d.jpg

For what it's worth, I have the same thing and had my mounts replaced with mazda comp mounts & it didn't help, could be different across NAs & NBs though. Those mounts still needed to be replaced, it looks like.

I replaced my motor mounts with the stiffer mazdaspeed ones also and that wasn't the issue. I am going to pull the driveshaft tonight and see if the transmission / clutch will still make the noise on its own. Good to see the OP fixed his issue with the trans replacement.

Same bastard noise
 

I posted the same video on YouTube of that clanking noise. Done all the obvious things like diff mounts etc.
started after putting in a new clutch. The noise eminates from inside the trans.
its not an engine mount. It’s not the exhaust. It’s not slack in the diff.
i took it to Skuzzle Motorsport and they just said that “they do that”.
I can’t accept that as an answer. Mazda don’t send them out the factory like that.
hoping it’s not a new trans. No reason for it to break on a clutch change

New parts
 

Changed the trans, rebuilt the diff, still no change at all