Jmlee44

Starting a poll on this since my 04 RX has ALL of the symptoms commonly described in the various threads on Club Lexus and on some of the Toyota forums on vehicles with the same drive train. Slow 1 - 2 shift, clunking and binding on 2 -3 and 3-2 etc.
I am going to start going through diagnostics with pressure testing the hydraulic circuits while monitoring the PCM's control of the various solenoids - in particular the pressure control.

I quickly threw a transmission gauge on it the other day, in 3rd gear idle spec is around 50-60PSI - mine was reading 25. I didn't get a chance to keep testing to see if the unregulated pressure was within spec (thus pointing to a pressure solenoid issue) - but I plan to run this down in the coming few weekends as time permits. I want to find out if it is more to do with electronic control issues or mechanical issues internal...

For me, it only happens once the transmission is fully hot. When you first start off, it is very responsive and seems just like any normal car. After a couple miles, its not so great but tolerable - and after an hour long drive - it really sucks.
Have any of you noticed a correlation between drive time (and by association, transmission temperature) and any of the shifting concerns or do yours do it all the time?

Hope you all can help. With input from folks with no problems and those with problems, maybe I can figure out something. I'm not ready to give up because "they all do that", not yet anyway.

ToledoRX

I had the same problems a few years ago when my RX 330 became my DD. The transmission was clunky at low speeds. I took it to the dealer to have them reflash it and also had them do an ATF flush for $140. It shifted like a dream after that.

My understanding is that the 5 speed ECT is an electronic adaptive transmission that learns the shift pattern of the previous owner. When it has a new owner with a different driving habit, it seems to develop this issue where the transmission doesn't adapt properly.

I doubt that it's a mechanical issue though, these transmission are well built and are supposed to last over 100k miles without maintenance. Maybe doing simple maintenance like changing the ATF fluid and having the dealer reset it can help with the low speed clunking issue.

Jmlee44

ToledoRX - you are correct they do adapt. The transmission fluid was changed with T-IV and filter done at the same time around summer of last year (trying to fix...this problem). We have dealer service records, the transmission has been regularly serviced so I don't expect neglect.
We have also reset the shift adapts multiple times, with an improvement that lasts a couple days usually then back to the same thing.

Really was just hoping to get a feel for everyone else's known good and known bad.

PhilD83

Pour a can of seafoam in the transmission (add some of the can to the power steering). Drive around for awhile, have the transmission drained, filter changed, and refilled with amsoil atf. Have the ps flushed and use seafoam atf. Have them clean the filter in the ps. I added a cardone inline filter. Now it is good as new on both. Every 30+40k miles, drain and fill the transmission with 4L of amsoil signature atf.