If I'm cruising at around 40 MPH, the car will sometimes produce a low frequency "shudder" that shakes the car. It fades in and out. Sometimes it will jump from a lower frequency to a higher frequency and back. Also, it sometimes feels like the transmission is slipping a little under the same conditions. I was thinking that it either had to be the transmission or the torque converter. The car has almost 140K miles and I drive it almost as hard as the Ferrari.
Looking to the AcuraZine brain trust for some ideas.
Thank you.

 

More information. The shifts are normal, not jerky. There is no problem during acceleration or deceleration. This only happens when I'm gingerly cruising at a constant speed with barely any throttle. Doesn't matter if it's cold or hot. And it has progressively gotten worse over the last few months.

 

Check your CV axles

 

I will. Thanks!

 

Okay the axles are good. Any other ideas?

 

How did you check the axles? Are the wheels balanced? Have you tried driving without a propeller shaft?

 

I drove the car to my indy (Foreign Affair) who I've had for over 25 years and asked the owner (Tim) to get one of his mechanics to check them.
Why do you ask?

 

After an extended test drive with one of my mechanics, he said the symptoms were classic torque converter failure. Curious as to why no one on this forum has mentioned that, especially when there's an active service bulletin from Acura addressing the issue.

 

Most likely no one has encountered such a problem due to proper maintenance of the automatic transmission.

 

Before we jump to trans, lets take a step back and look at the car itself. How old is air filter? Last time you cleaned throttle body? How old are spark plugs? What brand? What fuel do you use? What tires do you have on the car? How often do you change the transmission fluid? When the issue occurs, are the RPM's rising and failing by about 50-100 RPMS?

A scanner tool can be hooked up to your car and check that there are no issues with combustion at low RPMS, and as well can check throttle position sensor and other parameters before jumping to trans.

Dirty trans fluid can contribute to rough shifts and shuddering. If you drive the car hard, it's always best to change the fluid more frequently than suggested. The 6AT trans is a bit harder on it's fluid and it should be changed much more frequently than the manual states even when driven normally. I had this issue and the dealer did a 3x3 fluid swap before they had the software update. 3x3 fluid stopped low speed and cold judders

A tech can look at live data from the car and see if the torque converter is slipping, or the trans in the conditions you describe. If they don't have a high end scanner that can pull live data, then a torque converter stall test will show if it's slipping or not.

 

Shuddering at trying to maintain a constant speed was a symptom of a clogged EGR valve or ports with carbon for a Honda Odyssey I had - like going over rumble strips.

 

just curious what year was your Honda odyssey that had the clogged EGR valve?
I had a 98 Acura RL that one of the issues was clogged EGR valve and manifold port, they made the manifold port too small and they did a recall to enlarge the port and Re-sleve it but the old lady that owned my RL never got it done

 

Exactly the fix they did for my 2001 Honda Odyssey. Replaced EGR valve and cleaned EGR ports. One port was reamed as it was too small and a Teflon sleeve inserted.

 

Thanks guys for all the ideas. Will be tackling these one at a time.