I have a 2004 Honda Odyssey that occasionally produces a rumble noise around 30 mph (just before shifting from 3rd to 4th gear I think). The issue is pronounced if driving on a slight (10-20 degree hill or incline). Seems like a delayed upshift may be causing the problem. Any opinions on the cause or suggestions for repair.

Fyi....I know this post is several years old but if my answer can help someone it's worth it. I took my car to the dealership today for literally this EXACT problem on my 2010 Scion xB with 125k miles. I read this post and was shocked to read that someone else's xB was behaving the same way under the same conditions. In 4th gear at around 38 MPH and 1500 RPMs I get a vibration and a noise that, like the OP said, sounds like you're going over a rumble strip. That's the perfect wat to describe it. The dealership told me that it needs a torque converter. They want to charge me a thousand for the part and another thousand for labor because they've got to take the whole transmission out of the car and it's going to take 2 days (really 9 hours, they said, but they'd be keeping the car 2 days). I'm currently calling around to see if ANYONE can do it cheaper, but just in case anyone else comes here looking for an answer to this question, I hope this helps. Torque converter might be your problem.

Check out these sites:

http://www.edmunds.com/honda/odyssey/2002/consumer-reviews.html

http://autos.msn.com/research/vip/Reliability.aspx?year=2002&make=Honda&model=Odyssey

http://www.carcomplaints.com/Honda/Odyssey/2002/

had this problem myself. it turned out to be a sticky throttle cable from the throttle position sensor to the transmission making the transmission think it was in kick down mode. gave the cable a good dose of WD40 and its worked a treat ever since. and that's about three years to date.

Are you sure the trans is in 3rd. Pull the stick into low gear accelerate shift to 2nd about 20 mph shift to 3rd about 35 mph then 4th about 50 mph. This will let me know how to go further with your problem. If you do this proceedure write the results on this Great FixYa Page!

Depends on the throttle position, there is a adjustment for that transmission. I would suggest someone who has Honda experience, like a dealer.

It could be as simple as your tire balance is off.

Hi,

This might be because of the gear box problem. By any chance, did your car face flooding? In such cases, please drain the gear box and replace it with new gear fluids. Also, check if you go in low speeds, you might be able to engage it with ease. Please come back to me if you feel this doesnt solve your issue.

Regards,
Hari

It has nothing to do with the transmission, it's your engine mount thats bad.

I found this one the www.hondacarforum.com
http://www.hondacarforum.com/honda-technical/28562-i-have-1989-honda-integra-can-any-one-tell-me-what-s4-gear-stick.html

You have a couple of choices on this Honda transmission... D and S modes. Consider the D as the normal Drive mode and the S for Sport mode. The difference between the two is that in "D", the transmission will shift through the gears all the way to 4th gear and at lower rpm shift points. In "S", the transmission will shift at higher rpm levels and will go no higher than 3rd gear and light S3 on the dash. Once the vehicle is in 3rd gear (S3) you can then press the S4 button and the transmission will go into 4th gear (when conditions dictate). I believe there is even an S4 indicator on the dash signifying the trans is in 4th gear

The last line looks like it is the key here though.

If the car thinks its in 4th gear when you are trying to start it, obviously it wouldn't start...you could probably hunt around and see if there is a sensor on the transmission stick that runs the "D" vs "S" mode

Could be a lot of things (sensors like the MAF, EGR, etc) but I would first check the throttle position sensor (TPS).