My 2000 ES3000 with 76,000 miles started going to 4000 RPM while going 55 MPH consistenly. The RPMs are fine while idling. I don't think it is a transmission problem. Any suggestions on what it might me?

 

the engine speed is correct at idle?

when you're driving, you will notice the engine suddenly go from a lower RPM , then jump to 4,000 RPM?

do you have a blinking light on the instrumentation?
check engine light or transmission warning light(s)?

 

Yes the engine speed is correct at idle.
The faster I go the faster the RPM goes up.
It seems to be shifting gears smoothly,unlike other cars that I owned where u can tell it is slipping.

I checked the level of the transmission fluid, it is fine.

No instrumentation lights such as check engine etc are on(blinking).

I am stuck on this problem.

 

Your overdrive is not working (Not the O/D button). It does not go into final gear. (I think)

 

ur takin ur foot off the gas and this is happening?

 

Question is, can you feel it shift into the final gear or not? If your ES isn't shifting into O/D and your O/D off light is indeed off, then we have a problem.

 

True I cannot feel it shifting into the final gear. What does it take to fix the overdrive?

 

it sounds like you're in second gear which is not good... surprised you tolerate it, you ought to take it to the shop immediately