Drivetrain clunk
#1
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Drivetrain clunk
Hi all, long time no post.
I’ve recently noticed a clunk and a noise in the rear of my car. It seems to happen on cold starts, when I first roll out of my garage and right when i fully let the clutch out in first, literally within 10-20 feet. After this I can’t seem to be able to replicate it on the ground. I put the car up and tightened all of my PPF bolts and diff fasteners with no change. Posted to Trackable Miatas on FB with a few different suggestions, the worst of which being a broken tooth in the diff. I had a driveshaft go on me last year that I found under different circumstances and it was a very different sound, although I’m suspicious this one may be a u-joint issue as well. There is no obvious play in it, but again last year it was the same story - sound went away when I replaced my driveshaft. I hope my video has attached correctly. I have the car in the air and letting the clutch out in first. Thanks guys.
Further edit: there is only ONE clunk when it is on the ground. The rattle is different when in the air. I figured they were relevant.
Here is a YT link to the video:
I’ve recently noticed a clunk and a noise in the rear of my car. It seems to happen on cold starts, when I first roll out of my garage and right when i fully let the clutch out in first, literally within 10-20 feet. After this I can’t seem to be able to replicate it on the ground. I put the car up and tightened all of my PPF bolts and diff fasteners with no change. Posted to Trackable Miatas on FB with a few different suggestions, the worst of which being a broken tooth in the diff. I had a driveshaft go on me last year that I found under different circumstances and it was a very different sound, although I’m suspicious this one may be a u-joint issue as well. There is no obvious play in it, but again last year it was the same story - sound went away when I replaced my driveshaft. I hope my video has attached correctly. I have the car in the air and letting the clutch out in first. Thanks guys.
Further edit: there is only ONE clunk when it is on the ground. The rattle is different when in the air. I figured they were relevant.
Here is a YT link to the video:
#6
I'm going to go out on a limb and guess it's the pinion spacer (if OEM). I'm speculating that after several hard turbo launches and decel during autocross or track, the spacermight not be able to keep the bearing preload
I made this up, no clue. Symptom would probably be a screaming diff, not a clunk.
I made this up, no clue. Symptom would probably be a screaming diff, not a clunk.
#12
Gonna revive a dead thread and say to check if your flywheel is loose. My car made a nearly identical sound, and had what I thought was a rear main leak. When I pulled the transmission to replace the rear main, I found the flywheel had a loose bolt. Turns out my rear main wasn't leaking, as the oil was coming from behind the loose bolt. FYI the crank shaft leaks if you don't use thread sealant with loctite on the flywheel bolts.
#13
Gonna revive a dead thread and say to check if your flywheel is loose. My car made a nearly identical sound, and had what I thought was a rear main leak. When I pulled the transmission to replace the rear main, I found the flywheel had a loose bolt. Turns out my rear main wasn't leaking, as the oil was coming from behind the loose bolt. FYI the crank shaft leaks if you don't use thread sealant with loctite on the flywheel bolts.
Oh ****, I just I installed a new clutch/flywheel... I'll check my bolts when I install the new diff.
#14
Gonna revive a dead thread and say to check if your flywheel is loose. My car made a nearly identical sound, and had what I thought was a rear main leak. When I pulled the transmission to replace the rear main, I found the flywheel had a loose bolt. Turns out my rear main wasn't leaking, as the oil was coming from behind the loose bolt. FYI the crank shaft leaks if you don't use thread sealant with loctite on the flywheel bolts.
Now I am literally in the same situation you are. Just swapped my clutch for a Supermiata Sport Organic Sprung clutch. I am also getting ready to swap in another diff. I will say that I had the sound before the clutch install. Why are you pulling your trans when you install your new diff?
Last edited by atotalpro; 05-12-2019 at 10:53 PM. Reason: punctuation
#16
Now I am literally in the same situation you are. Just swapped my clutch for a Supermiata Sport Organic Sprung clutch. I am also getting ready to swap in another diff. I will say that I had the sound before the clutch install. Why are you pulling your trans when you install your new diff?
#17
I'm having a drive line issue when I launch. Horrible shaking/lurching. (Been lurking on this thread for ideas) One of the Old Farts™ at the shop I use said it sounded like oil on the clutch. I don't think that's it... BUT I always listen to Old Farts™ and I'll have the diff out (1.6 -> 1.8 diff swap) anyways. I torqued the bolts to spec but did not use lock tight on them. For just a few bolts I figure it's worth pulling the trans to check. /2¢
#18
I'm having a drive line issue when I launch. Horrible shaking/lurching. (Been lurking on this thread for ideas) One of the Old Farts™ at the shop I use said it sounded like oil on the clutch. I don't think that's it... BUT I always listen to Old Farts™ and I'll have the diff out (1.6 -> 1.8 diff swap) anyways. I torqued the bolts to spec but did not use lock tight on them. For just a few bolts I figure it's worth pulling the trans to check. /2¢
#19
I'm definitely going to go back and remount the flywheel. I have a FM clutch and a FX (I think) 1.8 flywheel. I can bang gears and clutch kick like normal, it's only from a dead stop where I have the issues. And it was fine on the 1.6 clutch...
It will be a while before I get to use the lift again but I'll post back then.
It will be a while before I get to use the lift again but I'll post back then.