Miata shifter and car shake
 

I took a video of what exactly is going on here.


So it all started with a metal clank as I let out my clutch. Only when under load, and only in reverse or first. I thought it was a suspension issue cause it happened on hills, (as I live on one) but as I checked the suspension bolts, bushings, and struts I couldn't find anything. Then my shifter started going crazy through first and second gear, but in third it doesn't go from side to side, just up and down quick and makes a shaking noise. At 30-35 no matter what gear I am in the whole car shakes really bad. I've done some research about the PPF and I can only see 4 bolts, 2 on the tranny, and 2 on the diff, and they are all tight and there. One was loose but didn't fix my problem. I tried shaking my engine for motor mounts, but it doesn't move as I also visually inspected them. Also all of the symptoms are gone when I am sitting there and I rev the car, so it has something to do with when load is applied to the drivetrain. Any ideas?

Time to invest in new motor mounts.

Didn't want to hear that haha. Does it have anything to do with the metal clank when letting out my clutch? I just don't see how those 2 correspond.

Your engine will try to move more against the mounts when trying to apply torque through the whole drivetrain. The car's an NA6? Miles? Ever had the mounts changed?

My bad, NA8 1994 236k on the body. The guy said he installed a new motor around 8k miles ago. I have no idea if he changed the mounts. Prob not.

I think your guess is right.

Time to get mazdaspeed competition mounts! My shifter's starting to move a tiny bit as well and I'm sure it'll get way worse with boost.

Yeah, perfect timing as I just ordered some RX7 injectors and a Megasquirt to finish my build.

Why? With everything that's available you order the oldest technology injectors there are?

it came with the Megasquirt. I wasn't gonna say no haha

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Took a few pictures to document the motor mount replacement. I got the Mazda competition mounts from MossMiata. The previous owner for some reason has the mounts notched out and the metal plate that goes over the mount is gone with Megan racing mounts on it. . Nevertheless it almost completely fixed my problem. Still a little bit of shake in first and the 30mph shake is still there but drastically reduced. I think it's a U-joint on its way out.

Some pointers are, remove the MAF for the driver side mount and take it out from the top when the bolts are out. Otherwise it hits the header and steering shaft, for the passenger side after you loosen them it comes out from the front of the car easily. Other than that it is very straightforward and shouldn't take more than an hour and a half.

The increase in vibration from the stiffer mounts honestly isn't terrible. Makes your rattles more pronounced haha, but not unbearable by any means.

I guess the previous owner figured it was easier to cut a hole in a place that would guarantee more vibration then just stick an extension in to loosen the nut. Pretty fucked up. Personally, I'd have changed that back to stock for what it'd cost. Then maybe you'd have no vibration.

Which MS this time? Third time a charm?

Wrong date. I suppose this is referring to the MS2.

Yeah, I'll give it some time and see what happens. I figured with the mount notched out it is way more flexible. Pretty fucking stupid lol.

DN, I ordered the DIYPNP at that time.

Those mounts are fucked, but I guess there's plenty of material left...

Also look into either poly or delrin diff mounts, that helps a LOT.

Will do, I was surprised how much engine mounts have on the shifter and car feel.

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Well, Miata is dead for awhile. That's my tailshaft. That's prob what was causing the vibrations along with my u-joints and it finally gave.

Fml that's bad alright. Is there any fix for this or the easy way out is a tranny w driveshaft swap?

For my case, I have to pull the tranny. So while I have to do that I'm pulling the engine, replacing the clutch, rear main, and a new driveshaft because my U-joints are shot anyways. Has anyone ever seen a transmission do this before?

That's properly fucked. Bad PPF alignment and a trashed driveshaft maybe?

wow, thats a new one on me. thats fucking awful. I dont think the PPF can be out of alignment enough to cause that. that is an odd one for sure.