Does anyone else experience the revs jump up rapidly from around 1900 to 2100 when just cruising on the freeway? There is no jerk or anything, its just as if when adding a little gas there is some slack in the transmission or something? Only noticeable thing is the rev counter.

 

Does it constantly jump up and down?
if so I believe your lock-up clutches within the torque converter are toast and failing to lock the converter.

this is due to not changning the transmission oil.

 

Its not all the time, I notice it a few times with cruise control on, mainly under very light loads on the freeway.
I just bought the car with 90k and replaced the trans fluid and filter, the oil didn’t smell burnt but was pretty brown.
Is there a way to diagnose those lock up clutches?

 

I periodically see this as well under the exact conditions you specify (light load, highway cruising ~70).

Is there a consensus that this is an issue or just an anomaly?

 

I ask because I have ~3 months of CPO L Certified Warranty remaining...

 

I might also add that I have been in Eco mode and have yet to test in Normal or Sport although I don't think it will make much of a difference as its not a CVT.

 

Cruise control exists to maintain a cruising speed and not engine rpm. So to maintain a steady speed, the engine has to accelerate and decelerate from time to time causing the rpm to fluctuate almost constantly. Even more so when encountering overpasses and such.

And the transmission logic being as it is in Eco will require more input to achieve the same acceleration.

Eco is for bumper to bumper traffic... leave your setting in normal.

 

Thanks!
I even notice the jump when driving manually around 70mph. The revs will drop to around 1800 / 1900rpm when coasting, then when I add a little gas it will jump very rapidly to 2100 then gradually increase as normal with the speed of the vehicle.

 

An update after a long road trip:

I noticed that with cruise control on and going down hill it will promptly seem to shift to a lower gear or out of overdrive if it has one. This causes the revs to increase as it is obviously trying to avoid letting the speed accelerate down hill.
The problem is it is too eager to shift down and then begins to hunt a little to maintain the speed. Does anyone know if there is a way to relax the tolerances on the gear shift logic?
The car is buttery smooth everywhere except going downhill with cruise control engaged.

 

I have never experienced a downshift w cruise on, but when going downhill, it does sometimes seem to 'hunt' for the right engine speed to slow the car.

It feels like very subtle jerks related to the rpm changes. Sometimes it does that a few times before settling. It's the only Toyota/Lexus I've ever owned that felt that way w cruise on going downhill, never experienced it in any of my Camrys or in my 2001 GS430.

It's very subtle; I doubt anyone else would notice.

 

Thanks, when I say downshift it is subtle so that's why I thought it may only be shifting out of overdrive?

 

Is this the 8 speed or 6 speed. If it's the 8 speed, my wife's Sienna does it all the time and did so since new. So I would say it's normal.

 

Im guessing 6 speed as its a 2013 AWD F Sport

 

Once or twice a year I take a roadtrip from Texas to see family in Phoenix and then I drive on to Vegas. Side note the GS with lux package is really a great road trip car. There are 3 places with long up/downhill grades, IH10 Kerrville Tx( northwest of San Antonio) has several very long 7 1/2% grades. I just turn the cruise off going down those. It downshifts 4 or 5 gears to maintain the set speed and revs start to get scary high. The other two are in Arizona the Wickenburg hwy between Wickenburg and Kingman. And between Kingman AZ and Hover dam. If you're cruising along in eco mode the transmission is much less likely to down or upshift. But on really steep grades that won't help you.

 

I do the exact same thing. If there's a fairly steep downhill, I'd rather turn the cruise control off as it'll downshift multiple times trying to maintain the constant speed but if it's steep and long enough, even with the downshifting, the car goes faster than the set cruise so might as well turn it off and resume later. I figured out to do this when I was on a trip from Austin to California where certain areas there are steep hills and the ones going out of SoCal to either NoCal or to Vegas.