AT car is shaking when cruising around 40 mph or so
 

When i'm cruising at 40 mph.. with the AT it revs pretty low in 4th gear at 40 mph and the car shakes sometimes when it reaches an exact rpm. I know it's the engine because the tranny is putting too much load on it in 4th gear revving like 2000 rpms. What can i do to get rid of this vibration? It's nothing that i'd worry bout breaking down or n e thing, but its annoying. When it vibrates, i either have to let off the gas, or increase throttle slightly.
BTW, its not an integra, but a CRV, but since there's no CRV forum, please help me out. thanks

Re: AT car is shaking when cruising around 40 mph or so (mingbling96)
 

It might be something wrong with your front end. Check your axles, joints, and other front end components like that. Good luck.

Re: AT car is shaking when cruising around 40 mph or so (integra-evan)
 

Similar problem in my corolla except at a certain mph, turns out to be a dead engine mount.

Re: AT car is shaking when cruising around 40 mph or so (PandaBear)
 

yes.. both the AC mount and the side tranny mount is torn.. last time i checked which is common with these cars anyways, as well as integras. .but i think its more than that. It's literally the engine vibrating because too much load is on around 2000 cruising at 40 mph. I know the engine is underpowered... like 126 hp for a 97 crv. I'd be cruising around 40 mph.. then all a sudden, the whole car vibrates... all i have to do is let off the gas or push the gas slightly and it goes away. Do you guys really think its really just the mounts?

Re: AT car is shaking when cruising around 40 mph or so
 

My 04 CRV does the same vibrating shake at 40 mph that mingbling96 describes Several mechanics have checked it out, up on the lift without identifying the source of the vibration/shake at 40 mph. When it occurs it only lasts 4-5 seconds and accelerating or decelerating will cause it to stop. Also, when it occurs it is always between 35-40 mph BUT when going through 40 mph it is not always present

My mechanic of several years did show me significant wear in the driveshaft so with 190k miles seemed sensible to replace driveshaft which we did and the noise/vibration continues. While driving on smooth roads with no traffic and staying between 35-40 I have tried multiple scenarios; braking in turns, accelerating/decelerating in turns, up hills, down hills etc trying duplicate the noise/vibration and if it does occur it does not appear to be due to the driving scenarios I've described

Tire wear patterns, alighnment, CV joints have all been ruled out
Any feedback would very much welcomed
Bartleby

Re: AT car is shaking when cruising around 40 mph or so
 

When was the last time you had your wheels balanced?

Re: AT car is shaking when cruising around 40 mph or so
 

Ditto the above^^^, wheel balance and alignment is the first place I would look, after motor mounts.

An easy/cheap test is to swap the front and rear tiers to see if it makes a diff, if so it is wheel balance.

I may also be worth checking the brake rotors to see if they are warped. 94

Re: AT car is shaking when cruising around 40 mph or so
 

A bad front axle can be the culprit. Only part besides the engine and transmission that is under load, under load.
Or as FCM stated, unbalanced tires can do it as well.

Re: AT car is shaking when cruising around 40 mph or so
 

I have the same problem as bartleby and mingbling96. I have ignored it and just let off the gas to remove the vibrations. It has been 1 year and now it vibrates every time I give it gas. Checked: alignment, balance, cv joints, brakes, valve clearances (regular basis) Replaced: spark plugs, cap, rotor, transmission fluid, fuel filter. Going to check engine control systems, does anyone have an idea of which one to start with?

Re: AT car is shaking when cruising around 40 mph or so
 

Check your motor mounts first for that type of issue. Most likely they're worn and need replacement if you feel bad vibrations.

Re: AT car is shaking when cruising around 40 mph or so
 

I changed the torn engine mount. It did fix the overall shaking but the original shaking at 35 mph is still there. My friends accord also has the same problem and has had it for years with no known solution. Has anyone else found a solution?

Re: AT car is shaking when cruising around 40 mph or so
 

Wheels are properly balanced?

Re: AT car is shaking when cruising around 40 mph or so
 

Balanced wheels, its been aligned, swapped out the rest of the engine mounts in case there was a tear i couldn't see.

One thing in common with both cars is that when engaging into drive the indicator light doesn't come on even though the bulb is still good. Also both cars, when engaged in reverse, takes a while to fully engage into gear and start moving. Could it be the Gear Position Switch?

Re: AT car is shaking when cruising around 40 mph or so
 

I doubt it. Its probably due to something that moves rather than a sensor. Is the vibration severe or just barley noticeable?

Re: AT car is shaking when cruising around 40 mph or so
 

It is most likely the torque converter, I don't know for sure if you have a lock-up converter or a non lock up converter. This sound like the converter chattering at the lock up speed. Drop the car down a gear and run the same RPM and see if the vibration is gone. I will bet the vibration is gone at that point. Lock-up converters are used for fuel mileage...

Yes it is violent. The entire car shakes. It's less now with new mounts but still there

That's right, it's not present in any other speed at the same rpm. So your saying drop the tranny and either re-machine the torque converter or replace it all together?

Re: AT car is shaking when cruising around 40 mph or so
 

Re: AT car is shaking when cruising around 40 mph or so
 

The converter chatters "vibrates" because it's on the edge of the lock-up/unlock made into it. Most have an electrical relay that controls this function, it could be as easy as replacing the relay. It could need a fluid flush and new filter with fluid. I would talk more with a reputable transmission shop about the converter. The vibration goes away because the converter unlocks when you give it more fuel which is similar to downshifting. The vibration isn't there at faster speeds as the converter locks up tighter. IF I dropped the trans I would just replace the converter. I would only replace it after talking to a reputable transmission tech however.