Jaxix

Hi,
I have a 2001 RX300, it was first registered 07/07/2001, has the new style lights, info screen and stereo, will this have the upgraded transmission? Is there any way to confirm ( serial number etc ) ?

I had a drain and change done at Lexus dealer last October along with the major service, and have just bought 5 litres of Type-IV ( 62 quid ), to do again this week, also got new oil for rear diff, transfer box and power steering after reading the superb instructional from Lexmex ,
so regardless I will be doing the annual maintainance on the transmission! ( but still hoping its the upgraded box )

Cheers Jason

trhs75

Hi, Jason! Welcome!
My understanding is that the sometimes-troublesome transmissions (I've had no trouble with my 99's) were just in the 1999 and 2000 models. Someone else more knowledgeable can chime in and tell you for sure. This forum is great; you'll get so much information from the nice people on here. Congratulations on your purchase!!

Jaxix

Hi trhs75,
got the RX off of my Dad a few months ago, he has had it since 30 000 miles,drove to southern Spain with the wife and kids in August, went like a dream, averaged 27 mpg.

Like I said before my only real worry is the transmission, no faults at present but always at the back of my mind,
so if any one knows how to identify a updated gearbox, it would certainly be appreciated!

Cheers Jason

kalali

You didn't say how many miles are now on the car but regardless, I would replace the transmission fluid at least every 15K miles. The 01-03 models might be a little better but RX300 trannys are overall weak. Our '03 with 164K miles is showing some issues, even with regular fluid changes.

hypervish

IMO, The transmissions themselves are not weak, the problem lies in the programming of the ECU.

I've read a lot on this subject, and that's my conclusion. The Sienna which weighs more than the RX and has the same transmission does not experience the same transmission issues (of course there are a few failures but not even close to what we see on the RX). I now own a Sienna and have compared the transmssion programming between both and can confirm it is different.

The RX300 shifts into neutral when slowing down and almost coming to a full stop. The issue lies here. Let's say you are going 2 mph, RX now in neutral, and the light turns green, you're instinct is to hit the gas. PROBLEM! You must very, very slowly apply throttle to get the RX back into gear and then apply more throttle. This is the biggest issue! And, a big problem when in traffic. SO I either use snow mode (stays in 2nd, no neutral) or just watch the tach to see it go into neutral and then gently nudge it into gear with a blip of the throttle.

I'm very careful in that regard now. I suspect that is the main reason the fluid got burnt so frequently. After about 2001, T/L added a larger capacity transmission pump from what I am understanding. This is also because of the programming. The RX will downshift right after it is upshifting. For instance, if you are in fourth gear at 40mph and the TC just locked, and now let's you are merging onto the freeway, and you get on the throttle hard the RX will downshift immediately, but the problem is the transmission cannot pump enough fluid to keep up with the downshift.

That is why T/L, introduced DBW to prevent this issue. Hence why many DBW T/L vehicles of this era experience DBW lag , such as my ES300. With DBW, it will wait till there is enough transmission fluid and line pressure before it allows a downshift.

On a side note, my RX has 200k miles on the original transmission and it's still doing fine! Drives & shifts like new. Same with my uncle's 99' AWD RX300 at nearly 400k miles. However we both do a drain and fill every 15k miles, the fluid comes out looking like new!

JAB

What does DBW stand for?

hypervish

Drive by wire.

Meaning the throttle plate is controlled by a little motor, no physical connection between the actual pedal and throttle plate/butterfly.

kalali

Hyper, I'm going to pay more attention and check your theory about the tranny going into N during deceleration next time I drive my wife's RX but I've always felt the RX has a a lot more engine braking compared to most other automatic transmission cars/trucks I've driven including my Jeep. Never felt the car was coasting to a stop in neutral.

hypervish

The part about the transmission going into neutral is not a theory. That is a fact.

My conclusion is just my theory.

kalali

OK, fair enough, you're saying the transmission goes into neutral as the car slows down and comes to a complete stop. So explain why the car does not roll backwards as you take your foot off the brake while at complete stop? Also, how do you explain the engine braking which slows the car down as you get to a complete stop? And finally, what purpose does this design serve? Improves fuel consumption?
Not challenging, just trying to understand.

hypervish

Yes, the transmission goes into neutral as you come to a stop (I believe 10mph is when it drops into neutral) and will only go back into 1st after the car has come to a complete stop. ("California rolling stops" are horrible for the RX).

The car does not roll backwards when stopped because it is back into 1st by the time you lift your foot off the brake again.

What is there to explain about engine braking? It does what it's supposed to.

The programming is meant to improve fuel economy, by nearly 10% if I remember correctly. It does this by upshifting early, locking the T/C at lower speeds (even outside of O/D gear ratios), etc.

Problem is this programming, requires so many shifts. Much more than required. In an effort to improve fuel economy, T/L took away from durability by causing so much unnecessary wear.

LanceA

Hello Im new to this forum & would love some advice. I recently purchased 2002 RX300 & have had nothing but problems. It seems to be in great shape with only 95k. I had all belts (including timing), fluids, oil & trans filters, plugs, water pump replace as preventative maintenance. I also had the knock sensors replaced too. It burned a valve in #2 3 days after maintenance & both cylinder heads had to be reworked. I took it to my shop twice to get that right, maybe. A day after I got it back the car is shifting erratically between 1 & 2, & 2 & 3. The car also leaked almost 2 quarts of synthetic in a 500 mile road trip from just above the power steering pump. Yet another problem with this vehicle or the shop forgot to do something. What was the fix on the shifting? New ECU or re-program the old?