Greetings everyone,

So the title pretty much says it all, but I suppose I'll include some more information.

So this is weird, I've never had any problems with this before, but on Sunday it suddenly cropped-up after getting off the highway. Essentially, the car is totally fine when accelerating in 1st and 2nd gear, but once I hit third, it starts vibrating really bad when accelerating. It also does this in fourth and fifth, but does not do it in neutral. The vibration almost feels like a back and forth; the only thing I can compare it to is when on my old 86 Bronco XLT 351, the harmonic balancer snapped in half while driving and I had a weird off-center vibration. I checked my plug wires to see if maybe one of them had popped off, but they're all fine, both into the plugs and into the distributer. My only other guess is the motor mounts, but I'm not certain how to check that. Oh, I should say that it really is only noticeable above 3k RPM. I can still feel it cruising in say, fourth at around 2k RPM, but it's much less noticeable.
As well, it does not vibrate at all if I put it in neutral and rev it up, whether I'm moving at 65MPH or I'm standing still.

Hopefully someone's had experience with this problem, as I really would like to fix it, I want to keep my Accord running for a good long time.

Thanks!

 

Your right to check the mounts. Not too hard to do. Different methods, I usually have a friend/one you really trust put the car in gear-parking brake on-and let out on the clutch slowly while checking for excessive movement. Do this in first and reverse checking all four mounts...best guess is the front-between the rad and motor.

However, there could also be an issue with the inner cv joints. When I started reading that was the first idea that came to mind, but the mounts could be an issue as well.

 

Thanks!

I checked the mounts the other day and the front's seem to be fine. I forgot to check the rears, so I'm going to do that today. I recall I had an old Taurus SHO that had some broken mounts and the engine shake was very excessive, the Accord looked nothing like that, at least in the front.

I had the tires balanced, as a friend suggested that (also a transmission flush) and that didn't seem to help at all. I'll need to check and see if they also did a rotation on the tires (I had my fiance take it), because I'm thinking it could also maybe be a bent rim on the front. After I had the tires balanced though, the vibration seems to be worse. Before it wasn't really noticeable in second gear, now it's definitely there, though not as bad as in gears above third.

How do you check the inner CV joints and see if they're okay? I assume crank the wheel to one side and get in their with your hands, feeling around to see if the boot is ripped and there's some dirt?

Also, why is it so difficult to check the transmission fluid? I'm worried that it's related to the trans, as about two years ago, one of the boots on the axles into the transmission was ripped and all the fluid leaked out. Cost quite a bit to have repaired and the shop put in a decent used tranny, so I'm a little worried it's related to that.

Could other suspension components be the culprit as well? My fiance suggested the struts, as she feels like her sister's car did the same thing when it's struts failed; I'm a little skeptical of that claim, as I feel like there's no enough evidence to point to that, but I'm not ruling anything out at the moment.

 

FYI, I would avoid having the transmission power flushed. The proper way to do it is to drain the fluid. Only about a third comes out. Refill, drive. Repeat 3 times to exchange most of the fluid.

If rotating the tires changes the vibration, then something is up with a wheel or tire.

As for the suspension, you can jack up the front of the car on jackstands. Turn the steering wheel until it locks. Try to push/pull the tire at the 9/3 the the 6/12 o'clock positions. There should be very little movement in the tire. If there is movement, try to see which ball joint is loose and replace.

 

"As well, it does not vibrate at all if I put it in neutral and rev it up, whether I'm moving at 65MPH or I'm standing still"

If this is correct, it suggests more likely problem is a motor mount. Shifting into neutral almost fully relieves the engine torque response. Since vibration stops, it suggests a mount problem. Check front and rear mounts closely.

This also eliminates suspension problem since this would be unaffected by shifting to neutral.

good luck