Manual Stick Shift Lever Vibration

[MRC01]

In my 2014 Mazda 3, manually tranny, a few months ago while coasting down a hill in 2nd gear I heard a vibration. Turns out the stick shift lever was vibrating enough to make a little noise. Over time, I've found it happens intermittently, only in 2nd gear, can happen under coasting and under acceleration, the vibration is not noticeable below about 3k RPM. When it happens, the vibration is just enough to make a sound and visually see the lever moving, not enough knock it out of gear, and if I shift to neutral then back into 2nd, the vibration disappears.

Any ideas on troubleshooting? Perhaps a shift fork or other part of the linkage sometimes doesn't align properly when shifting? Why only with 2nd gear?

This car has a TSB for popping out of 3rd gear. But I don't think this is applicable here. It has never popped out any gear, and this vibration happens only in 2nd gear - not 3rd.

 

[supton]

Motor and/or transmission mounts?

 

[Jetronic]

my guess is a cable is wearing, maybe they are adjustable.

 

[MRC01]

Motor and/or transmission mounts?

If so, why only in 2nd gear, and only intermittently, and why does it fix itself if I go to neutral and back to 2nd? None of that would affect tranny or engine mounts.

 

[JRay’07]

2nd gear often sees the most abuse. Have there been any bad shifts (intentional or not) into this gear in the past?

 

[supton]

If so, why only in 2nd gear, and only intermittently, and why does it fix itself if I go to neutral and back to 2nd? None of that would affect tranny or engine mounts.

Loading/unloading of the assembly, causing a mechanical shift.

Pure guess.

 

[JHZR2]

The gear shift in my 135i moves… since new. Not a lot, but enough to notice. Unlike all the other my cars and trucks I have owned.

It must have to do with isolation.

If just in one gear, it sure could be how the gate springs, harmonics on the chassis, etc. all play together. It wouldn’t be unforeseen to have it behave in one direction/orientation but not another.

 

[MRC01]

2nd gear often sees the most abuse. Have there been any bad shifts (intentional or not) into this gear in the past?

Not that I know of, and I'm the only driver.

 

[eljefino]

Gear shifts and their cables are often rubber isolated so this doesn't happen. This leads to less-than-sporty shift feeling. It's probably a combo of the over-cable and the down-cable getting the most wear, going for 2nd gear, because a lot of people kinda cram it in gear, fighting the synchros on a downshift-to-corner.

 

[MRC01]

Possibly. I figure it must be something not seating entirely right, because it's intermittent - sometimes perfect, other times it vibrates. And when it vibrates if you shift to neutral and back that fixes it. As if doing so re-seats or re-positions whatever wasn't seated right.

But exactly what isn't seating right, I don't know. Even when the stick shift vibrates, it is fully engaged in gear and never pops out.

 

[Jetronic]

the dog teeth will prevent popping when sending power through unless worn.

 

[JRay’07]

The only other theory that I can come up with is that the harmonics on the engine side are either being amplified or cancelled out by other drivetrain parts. Repositioning the engine relative to the rest of the driveline fixes the problem, as you have stated. We are assuming that your harmonic balancer (if equipped), clutch and flywheel are intact and in good working order.

 

[MRC01]

The only other theory that I can come up with is that the harmonics on the engine side are either being amplified or cancelled out by other drivetrain parts. Repositioning the engine relative to the rest of the driveline fixes the problem, as you have stated. We are assuming that your harmonic balancer (if equipped), clutch and flywheel are intact and in good working order.

The engine runs smooth from idle to redline, the car drives smooth at all speeds, the vibration is in the stick shift lever only, and only in 2nd gear, and even then, it's intermittent.

I didn't state that repositioning the engine relative to the rest of the driveline fixes the problem. Shifting from 2nd to neutral and back to 2nd does fix the problem.

 

[MRC01]

BTW, this is a tricky one. If it were easy I would have solved it months ago and not posted to get advice.