So i have a 00 RX300 with 170k miles on it. It started shifting hard on occasion, and sometimes hesitate to shift, even making a clunking sound on the shift. This is my wifes car and didnt want to leave her stranded, so i figured with 170k miles it was time for a new tranny, so i bought a rebuilt one and had it installed. All new tranny, torque converter, flushed tranny cooler and lines. Now i got it back and having about the same issues. No difference. sometimes shifts great and sometimes shifts hard, or will hold at 3k rpms for 5 secs before shifting, or when going down hill in 3rd gear and coasting it will jerk to shift into 4th. No codes are found. I have no lexus dealer within 90 minutes of me, so i took to a toyota dealer after the shop that intall tranny didnt know what to do, the toyota place said no codes and that it did shift hard, but didnt know what to do and i had to take to lexus dealer. before wasting all day, maybe more i figured i would get some suggestions. Tranny fluid is new toyota fluid and at proper level when warm. Could it be the computer? if so can i just get a used one and install it? i want to just sell the rx since i have gotten her a newer one now with this issue going on. i have been driving it for about a week and runs perfect other then the shifting.

 

Go to Lexus Dealer to have the ECU memory cleaned. It requires a special tool. Some Toyota dealer may have the tool.

 

I called the dealer and asked them about that... and they said disconnecting the battery for 20 mins would do the same thing, so i did that, and no differences.

 

Read the bottom part:

http://www.justanswer.com/lexus/4y9j...nsmission.html

It requires a special tool. When I got my trany replaced, I also had this problem. After paid $125 for 10 mins job of cleaning ECU, the problem gone. It works.