I know you already mentioned you cleaned the sensors and it was easy. The 2 sensors are exactly the same. Now the only step you need to add is drop them back into different holes when done. Then take it for a ride. If the problem remains the same, you have ruled out the sensors. If your 1st to 2nd slip has changed to something else like 2nd to 3rd slip or reverse problem, you know one of the sensors is bad. Order 2 new ones.
When I tried this my problem went completely away and has not returned.

 

I guess I will have to try that.BTW what was your trans. doing that made you swap the sensors?

 

Mine had the reverse problem. My guess is one of these sensors causes the reverse problem and the other the foward slipping problem. I wouldn't wait too long to see if sensors will fix the problem. I am sure all that slipping is causing some kind of damage in the trans.

 

UPDATE: Swapped sensors over the weekend and still no luck. Though I have noticed the transmission slips only while under moderate acceleration. if I am really easy on it ( not accelerating above 2,000rpms) then it shifts fine. Strange. The transmission shop thinks its might be a solonid pack? anyone heard of this?

Thoughts?

 

It it were those, they would throw a code. I think we've had a few people, less than 5, who have had this issue over the years. They require removing the pan and then taking off a lot of screws to access the area where they are.

 

I think you have to remove the valve body, but I cant remember for sure to remove the solenoids....

 

So No codes at the shop today. Strange. Still slips occasionally. when I really feather it no slipping at all. Its almost like it misses engaging when shifting from 2-3rd then it engages and does not slip after that. all other gear shifts are fine.

Shop said rebuild it. I am not ready for that yet. I am taking it to a trannsmission shop this week. The guy says he has done a few RX 300's. any other ideas?

 

i been having the same problem also 2 year i gave up on it cause i rarely drive my car... it never threw any codes at all.. i replace the transmission 2 times and replace the solonid still having the same problem. i talk to my buddy at lexus he said to make sure who you get your tranmission from has a warranty on it because he work on a couple of rx300 with the same problem that i been having .... he had replace transmission 4 times until the problem went away.. its the company who making the transmission doing a bad job on them and these are the company lexus trust to get there transmission from or rebuilt at. if you do replace the transmission and when you notice something is not right take it back right away cause warranty only good for 1yr or 12000 miles.

 

Somebody on here got a really good warranty at a private shop.It was like a five year warranty or something.How is Aamco,and Cottman? are they any good? We also have a Lee Miles transmission shop here where I live.If mine goes,I was thinking of a private shop to do the job.But I want the best warranty too.

 

I am being quoted 2 year 24 thousand mile warranty from a local shop. Never trusted cottman or Ammco. I have had bad expierences with both shops. They are not worthy of working on any tranmission from what I have seen.

 

Well took it to an independent here in Mesa arizona and they re-built the transmission and its doing the exact same thing as before. They are now telling me that the computer is not "learning" the new transmission and drive style.

Any suggestions on what to do next?