Rep Power: 0

I have a 04 Civic LX Sedan A/T with 44,000 miles.........I know, I know....... Driving down a flat road at 40 to 50 miles/hr. with the transmission in 4th gear (approx. 1500 rpm) while going up a slight hill or attempting to accelerate gently I get a fairley strong vibration in the front end. This condition worsens with more weight in the car. This only happens in 4th gear. If it down shifts to third the vibration goes away. I have no other problems at higher speeds or in other gears. I have checked the alignment and balance of the tires and the toe-in is sat. I did think that it might be a CV joint or bushing(s), but the fact that it happens only in 4th gear and at no other time makes me lean now towards a possible trans. issue like the torque convertor/vacuum line issue. It's been going on now for the last 25,000 miles - almost 2 years and getting worse.

Any help would be greatly appriciated.

 
Rep Power: 380

With it only happening in one gear... thats definitely something a shop will need to look at.

 
Rep Power: 0

I've taken it to my local garage and to the Honda dealer. Both can't figure it out. Honda hooked it up to see if they can find any codes and there were none. I even took the mechanic on a test-drive. Left the car for two days and they said they tried to fix it. When they couldn't do anthing with it they said it was a "normal function". I then asked the service manager if I could test drive another 04 civic. Of course "none were available" so I wrote a letter to Honda Corp., and their reply was that unless the transmission or suspenssion fail they can't do anything about it.

My local garage guy said that the alignment was perfect (gave me a print-out) tires are in great shape (less than 10K on them) and everything under the hood "looks good".

 
Rep Power: 380

Where do you feel the vibration?

in the steering wheel? in the dash? in your seat?

 
Rep Power: 0

Front-end and only a little in the steering wheel. Nothing in the seat. Even more noticable shaking felt when I ride as a passenger in the front right seat at my feet and towards the firewall..

.....Just to add to this. It seems as if the vibration feels more vertical in its shaking and the car has a slight tendancy to pull to the right when it vibrates.

 
Rep Power: 380

Thats got to be engine/transmission then. If it were the front wheels you'd feel it in the steering wheel.

 
Rep Power: 0

I think you're right. I just took my car to my friends mechanic who's a really sharp guy and he lifted the car and did a really thorough check of the entire suspension and asked me lots of detailed questions about this and he came to the same conclusion.......Transmission. $$$$$

He specificly thinks it's the torque converter when it locks into 4 (top) gear. He knows a good trans guy that he said he could have it checked out for sure. He also said that I wouldn't have any codes unless a solenoid valve failed etc......... He did think that I should have a flush of the transmision to start and then go from there. I told him I had a flush about a year ago.....He thought that they might not have done the flush properly.........

Zzyzx..thanks a lot for your help! I let you know what I find out next week.