Stemmer

I posted that my transmission failed and was replaced under CPO warranty at 90k and it's now 206k. Been doing drain/refills every 15k. For at least the past 6-months when I first start driving in the morning I reach a slight incline about 1/4 mile from my house and am traveling between 30-35 mph. At that point, every day, my RX delays shifting to the next gear and revs for about 30-seconds with the RPM's going to about 3,250 before finally shifting.

I told a friend of mine who knows a lot about cars. His opinion was as it only takes place first thing and never after that, the transmission is cold. He recommended warming the car for a minute and then slowly shifting from park to low gear back to park and then drive. I did it yesterday and today and it worked, smoothly shifted at about 2000-2250.

Wanted to let the club know this in case anyone else has this symptom, but also wondering if you all recommend I warm and shift every day or if it seems the symptom is just from being cold, to not worry about the single delayed shift.

salimshah

"warming up" has different meanings and different impact.

Standing still and letting the engine idle is the default "warming up". It basically heats up the engine block and exhaust system. One of the worst impact is on the environment (please excuse me for owning a SUV and talking about environmental responsibility), and energy waste. The heating up can be done more efficiently if the driver starts driving slowly. Energy is put to good use and the load helps engine warm up faster. Thermostat prevents any moving cold air to chill the engine.

The transmission heating predominantly happens by stressing the transmission fluid and very little by conduction (engine block to transmission housing). To warm up the transmission the best thing is to drive once again.

Based on the above, the design and the recommended use is to start and drive slowly to get to the optimum temperature (maximum engine efficiency point) . RX is notorious to hold the transmission in low gear till things heat up.

Your friend has good advice that you should let the engine warm up, but it should be done while driving slowly.

Roving the gears should help fill up various chambers in transmission.

[Opinion: If you live right by the highway, and need to get to 60mph with transmission locked out of higher gears ... you are stressing your transmission. You need about 1.5miles of slow driving]

Salim

LA4Mead

Mine's an early '99. Don't the '99's need to warm past (the same temp as shown by) the first mark on the temp guage before they will shift from 2nd to 3 before 3,000RPM? That's how they were designed (hate that).

Best cure for that is as Mr. Shah said, warm up driving slow, don't attempt to get going much beyond residential speed until the beginning of the warm cycle is complete. That and clean engine oil always. I've always hated that about my RX. I thought they changed that delayed cold 2-3 shift on later model year RX300's; I don't think my friend's 2000 did it. I thought it was a way for them to get LEV emissions rating quickly before doing some extra engineering.
I just baby mine until the temp guage starts rising anyway. It's a good idea; I just wish I wasn't forced to because of the extra RPMs.

Lexmex

If you turn on the RX300 and let it sit, about 13 minutes later, coolant mark should be at about normal.

However, when I used to go to the track, if I turned it on and let it sit about 3 to 4 minutes from cold, then it would shift normally, without needing to wait for warmup.

It takes roughly between 1-2 minutes from a cold start and driving to get it warmed up to shift normally.

dhealy

For Toyota ECT transmissions, the ECU prevents shifts to 3rd and Overdrive until water temperature reaches between 122 and 162 degrees Farenheit (Varies in different models and I dont have specific RX numbers). How you choose to warm up your vehicle is your business but letting it run for 2-3 minutes before heading out in the morning is probably your best bet.

dansandieg

I have a 2001 RX300 with 155K miles. 45 days ago I had a local transmission shop put in a rebuilt transmission (previous tranny had failed). Since then I am experiencing the same issues mentioned in this thread (shifting is hesitant for first 5 minutes of driving each day). I never experienced these shifting issues in the RX before the tranny change.
Do you think it is possible they installed a rebuilt '99 RX300 transmission in my '01 RX300? Is there a way for me to check this (e.g. an identifying number on the tranny)?
Thank you.
Side note: What a pain this tranny change has been. The first tranny they installed was DOA within days of install and this is the second rebuilt tranny they have put in. I am going to ask them for more details on the tranny to see if their supplier has known issues.

kalali

The only other point to keep in mind is that the transmission fluid runs thru the cooler next/within to the radiator so there is some heat transferred to the fluid as the coolant warms up, either by driving or idling.