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Discussion Starter #1
Hey all, hopefully the community here can answer my question because no one in my "real life" contact list can figure this one out...

My manual-transmission car will violently shake back and forth when (what i call) the car "pulls". Meaning uphill or otherwise pulling the car harder than it needs to in a normal "cruise" speed. And after re-reading this, im really not sure that it even makes sense.

- First and Second gear RARELY do it, however 3rd gear is usually the prime gear that this occurs. The shaking starts about 2 seconds AFTER i shift (successfully) into gear. Ive never seen it happen to 4th gear.
- Once it starts its shaking, i can either let off the gas and it will stop immediately, or i can floor it (thus applying more gas) and it will stop as well.
- The car, while shaking, will accelerate normally. There is no noise, no clacking, and no smell. I maintain proper speed and it will eventually calm down (usually because i throw the clutch in and shift to 4th).
- It doesnt appear to be an RPM issue, as it can vary depending on what state my car is in (pulling vs. slow accel)
- My number 1 suspect was the spark plugs, but i replaced those and it still happens. I have done all of the normal maintenance i can think of. Still happens every day.
- No check engine light

I would appreciate ANY help you guys have...even if its just a suspicion...thank you!
 

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Discussion Starter #2
Hate to bump my own message, but like i said...i have zero help and id hate for this to turn into a serious issue that could cost me way more money. If i did not provide enough detail, please let me know and i will try to explain further.
 

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Discussion Starter #4
I appreciate the response, DrSalt.

I dont believe it is the way i am shifting in and out of gears. My transitions are noticeably smooth, and also it has a different "feel" when i pop the clutch. The transmission and clutch all feel normal, but the shaking is just a little weird. It happens more on an uphill and has different degrees of shaking. Some are very subtle while others are violent. The only thing i was suggested that i havent done, are fuel injector cleaners.
 

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Tuscloud said:
I appreciate the response, DrSalt.

I dont believe it is the way i am shifting in and out of gears. My transitions are noticeably smooth, and also it has a different "feel" when i pop the clutch. The transmission and clutch all feel normal, but the shaking is just a little weird. It happens more on an uphill and has different degrees of shaking. Some are very subtle while others are violent. The only thing i was suggested that i havent done, are fuel injector cleaners.
If it's only in certain gears, it could be a tranny issue... Press on the gas a tad more when it starts to shudder. Maybe it's your 3rd gear synchro?
 

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Discussion Starter #6
I am hoping it isnt the transmission (for obvious reasons), but alas im wondering the same thing. To clarify: it has happened on gears 1, 2, and 3...but it is highly reproducible on 3rd gear.

I am not familiar with the 3rd gear synchro. is that something i would be able to investigate myself (or with family/friend mechanics) or is that something i would have to bring into a shop to have looked at?
 

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If it is happening in all three gears then it isnt the gears. All three wouldnt be going at the same time, unless you like to slam shift with out the clutch. Something is loose or out of balance, like the driveshaft could have mud or debris on it that would throw it out of balance. The flywheel could have built up friction material from the clutch disc and unbalanced it, or it could be a motor mount.
 

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Discussion Starter #8
Perfect. I will take a look at the driveshaft or flywheel. Like i said previously...i know its not my driving. I dont force anything and i shift appropriately. There isnt any shaking whatsoever if i floor it. So im not sure it could be a motor mount. I guess its just a matter of inspecting each component...something i was hoping to not do. But thank you for the suggestions.
 
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