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I have a 2008 Honda Civic with a Manual Transmission. I've been battling a severe shaking for a couple years now. The car shakes with a frequency equal to the rotation of the tires. It is especially bad at 70mph but it goes away if I coast, however downshifting makes it come back. It seems as if driving in a condition where the driveline has no stress is smooth but accelerating or downshifting starts the vibration.

Here is what I have tried already:
Nothing on this list has helped.
-Checked ball joints and steering links, good.
-New CV axle shafts
-New Wheel Bearings, twice
-New Brake rotors and pads
-Tires rebalanced
-Steel wheels were run on a spin balancer without tires on and check out perfectly true
-New tires installed and balanced
-Engine Mounts checked, seems acceptable
-Checked for misfiring, is not misfiring
-Control Arm Bushings are good
-Put car on a lift and idled in 5th gear, drivers side tire bounces up and down
-Rebalanced drivers side tire, was not out of balance.
-Installed new drivers side wheel bearing and CV shaft
-Still vibrates violently, nothing has helped thus far.


Any suggestions?

 
Rep Power: 243

Hub?

 
Rep Power: 0

New hubs came with the first set of wheel bearings. The car seems to go through wheel bearings every 10,000 miles.

 
Rep Power: 243

Are you using OEM parts? I expect Honda suspension components to easily go 100k miles.

 
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Not OEM but I'm using Napa Gold, the bearings have a warranty so I haven't had to pay for new ones after buying the first ones. I'm sure the bearings are failing early from the vibration.

Can a manual trans cause the car to shake? Also, the clutch is not slipping. How loose should the CV shaft be in the transmission? I looked under it last night and there is oil around where the spline shoves in the trans on the drivers side. The shaft seems to be able to lift up and down in the trans 1/2 inch and the seal on the trans is leaking. Does that mean I need a new bearing on the transmission?

 
Rep Power: 210

Start by getting a Road-Forced tire balance...if, you haven't already. I've had issues with regular (non- road forced) balances that a road forced balance corrected.

 
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Wouldn't getting new tires fix that?

 
Rep Power: 210

Absolutely not. All new tires rims/tires need balancing. Road-force balancing machine simulates high speed driving conditions. Read: https://www.discounttire.com/learn/road-force-balancing

 
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I know they need balancing, I have a spin balancer. It is a Hunter DSP9000. I thought road force balancing was gimmick to upcharge customers or only needed for low profile tires.

 
Rep Power: 210

Road-force them and Roadhouse the vibrations.