transmission fails to shift to high gear or overdrive on intermittent basis

http://www.2carpros.com/questions/1999-lexus-rx-300-no-shift-into-overdrive

I put that alone in a window to make it easy to hyperlink. The is a shift solenoid for O/D inside transmission, problem is I don't know which one. Click for full screen

Now, this one has all the info, but in Arabic. If you want to go to all the trouble of using Google translate you (we) can probably learn something http://www.mekshat.com/vb/showthread.php?t=352780&page=45

one more

http://dannymaddox.com/lexus-rx300-wont-shift-into-overdrive/

That one says: For whatever reason Toyota engineers programmed an over drive lockout to force you into a service bay and to protect the engine. Like me, you’re probably shaking your head in disbelief that something like not having a gas cap on can cause an OD lock out. Just leave your gas cap off, run it down below a 1/4 tank, hit the freeway and see what happens.

better focus than other schematic

By far and large the number one culprit for not shifting in to Overdrive is cold temperature. Lexus RX300’s will not shift into OD until the transmission fluid is up to operating temperature. This is a royal pain in the ass but is normal.. --Danny Maddox

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Figured I would chime in, and add my experience for those that stumble upon this... 2000 Lexus RX300 doesn't shift out of 3rd at highway speeds. At 60 mph or so, I'm at 4,000 rpm, and from the driver's seat it feels like fuel is cut for about 2 seconds, and rpm's fall (even when holding accelerator pedal still). If you let off the gas slightly and reapply, you feel a slight "clunk" as the transmission picks up drive again. But no problems whatsoever in gears 1 through 3 around town. I initially thought it was a tranny issue, but I read above that overdrive is not allowed when there's a check engine light (which I have from time to time). Today I didn't have a CEL, so I hit the highway to test the theory. Sure enough, with no check engine light, everything runs perfectly. Good to know that a transmission problem is not to blame. Thought I would share in case someone else is experiencing the same issue.

bikesin, how did you figure out how to turn off your check engine light? thanks ,Rob Lane rob.lane16@gmail.com i have 2000 Lexus rx300, does exactly what your talking about

My nephew is a mechanic. His scantool pointed to a cylinder misfire. He replaced that coil pack. That didn’t solve it. He finally traced it down to a faulty VVT solenoid. He went ahead and replaced both VVT solenoids since he was already in there. Also cleaned the mass air flow sensor and throttle body. All is good now. No more check engine light, and now it shifts into overdrive as it should.

Just to clarify, this is "bikesin". Not sure why cargurus changed my screen name when I responded above. I didn't want anyone to be confused. Anyhow, my issues were solved by replacing the VVT solenoids (both), cleaning mass air flow sensor and throttle body. Less than $300 total with labor. Hope this helps.

You can buy a FIXD plug in unit that checks for codes but also will reset the codes in your vehicle. It is a little white box that plugs in where the service guys or autozone type stores. The plug in area is under the dash on the driver's side. Works great.

I have an RX300 AWD Year 2000, which does not go past 3rd gear on the highway. Discovered the problem was with the control board. As soon as I bought a control board and re-configured it the car started picking the 4th gear again. However not the overdrive. Changed the ABS motor and the car got stuck in 3rd gear again. This time the engine got burnt.

I had similar problem with my 2002 Lexus RX300 all wheel drive with 230K miles. The VSC and CEL indicators came up and every time disconnected the battery to clear the indicators then they would come up again. Every time indicators came up, I would experience the overdrive problem. After I replaced the air filter and cleaned the MAF sensor the problem disappeared. I noticed that the glass tip of the MAF sensor was quite dirty on one side. I dipped it in the cleaning alcohol and removed the dirty stuff with fine brush.