Since the outside temperatures fell to teens and sometimes into single digits, I noted that my RX has developed something I do not remember from the past two winters: in the morning, the RX has poor downshift quality - when I start driving it upshifts just fine, but when I need to slow down it "feels" like the transmission wants to stay in higher gear, that is it downshifts but later than I would expect and I can feel the downshift as well. After driving for 2-3 min. the problem disappears. I always warm up my RX for at least two minutes or to the point when the tach reading is <1K rpm
I called the dealer and the SA told me that in cold weather I should warm it up "for at least 15 to 20 minutes, if you don't you may damage your transmission". When I told him that idling the engine does not warm the transmission because the insides of the transmission do not move, he replied "It's true but the pump is working and the fluid is moving."

Any one has the same/similar problem? (if it s a problem in the first place...)

Any one was told by Lexus' SA to warm their RX for 15-20 minutes?

Thanx

PS
My independent mechanic once told me to warm up a vehicle w/ transmission in Neutral because than some parts of it will move.

 

Dealer nailed it.
The hydraulic oil in the trans. is just as cold as the engine oil. With the engine spinning it's moving the oil through the pump & the oil pan. Might be some pressure applied to various internal galleries & passages.
The fluid movement will warm it & result in an easier flow.
Part of cold Winter driving locally. We're at -25C + the windchill here today. She parks the RX in the garage but I get to warm up The F150 outside every morning.Same basic technology.

 

No, it's not normal, and there is no way you should need to warm up a modern vehicle for 15-20 minutes. That's a waste of time and fuel, and a poor excuse from the dealer.
I would persist to get it fixed.

 

At the risk of possibly embarrassing myself, I find the notion of warming up a car for 15-20 minutes to be counter to everything I've read about cold weather operation, and I've driven in
Vermont for 45 years.

I've repeatedly read that just a minute or so of warmup is proper, just as long as you don't immediately take off at 60 mph. Just start the car, start moving, and in a few miles
the engine and transmission will warm up appropriately.

I just can't buy the notion that warming up a car for 15-20 minutes is beneficial. In fact, I believe
it to be bad for the engine.

Anyone else care to chime in?

p.s. glad to see jrfiero agrees with me. The dealer statement completely baffles me.

 

You're correct. After starting and waiting just a few moments when it's really cold, drive moderately to warm it up but not with high revs or high speed till engine temps or normal.

 

My 2013 does the same thing. I posted a video of the blip in the rpm when coming to a stop.

https://www.clublexus.com/forums/rx-third-generation/732638-transmission-rev-slip-from-2-to-1-in-when-cold.html

 

Yes, that is what I hear/feel as well. It did not fell like a clunk, and usually goes away after 1-2 min. of driving.
Did you go to a dealer with this?

Thanx

 

I just can't see how fluid movement would warm up the tranny - usually engine (and tranny) warms up from friction forces generating heat. If the RX idles in "Park" I can't see how it would warm up the transmission because the internals of the tranny do not move. I can see when in "N" some parts of it move but w/o load how much friction is there?

 

I have my scheduled oil change coming up in a few weeks. I'm going to bring it up then. I had the same issue with my 2003 golf GTI. Lived with it for 11 years. Found out it had a Japanese 5 speed auto tranny by aisin. So maybe it's a common thing, is the Lexus tranny an Aisin 6 speed? Time to google

 

The fluid is forced through the pump vanes in the torque converter when the engine is spinning, driving the main hydraulic pump , into the galleries around the transmission case, in & then out of the transmission cooler all causing a bit of friction. All this oil has a common reservoir in the trans. pan
The main input shaft is always spinning with the engine turning, rotated by the hydraulic pump assembly which is rotated by the torque converter.The converter is basically a hydraulic coupling between the engine & trans..

It's the output shaft that doesn't move until the mating clutches are forced closed by the fluid pressure in an auto shift car when put into D.

Doesn't take a lot of time, not sure a 15 minute warm up is really needed. Ambient temperatures will govern. You'd be surprised at the heat generated just by circulating the fluid. Whether it's our RX, the F150, the Honda or the nieghbor's Benz, they all operate generally the same.

 

I usually let it warm up for maybe a minute. I am not sitting there for 15 minutes running my car, that is ridiculous and terrible for the environment. I am curious if the owner's manual says anything about cold operating temperatures.

 

Thank you,
Since the temps are up now, there is no problem- I will "save" the issue for the next winter since there is one more year of warranty left on my RX

 

Best bet is to follow recommended procedures with respect to fluid levels & fluid changes on the transmission.
Believe most FWD transmissions do not have an external filter but have a filter element inside the case.
Not sure about Lexus/Toyota V6 transmissions as on our cars. Can be a real chore to access it.
Clutch filings will present themselves at fluid changes, normal wear & tear, to a degree.

 

Our transmissions are made by Aisin, same as your Golf. Aisin is owned by Toyota! They supply several other manufacturers with automatic transmissions. My 2008 MINI Cooper S had an Aisin 6 speed automatic. Fluid fill procedure was about the same as Lexus. No dipstick either!

 

Yep no dipstick and had to drain and fill with the GTI... and now Lexus . Funny i thought I was actually changing car manufacturers lol