yaro1

I was traveling down a moderately steep road the other day (which I have traveled down many times) and I noticed this. The speed limit downhill is 35 but going less than 40 is more of a hazard of being rear ended than a safety issue otherwise. Therefore, I was going down with the traffic at near 40 and when the truck began to pull forward more on the hill, I eased the brake in for about 1 second and the transmission lowered the gear and the RPMs shot up. I took my foot off from the brake to coast and the GX maintained the same 40mph down the entire hill within 2 mph. Normallly, coasting would result in well over 50mph by the bottom of the hill. Then, when I reached the bottom of the hill and the road flattened, the transimission upshifted without me applying throttle and I drove on.

Is this normal operating behavior for the GX? I know the truck has a feature that holds a gear while going uphill but I noticed this for the first time after 30,000 miles with the truck.

(No, this was not Downhill Assist Control either and I was driving in D like normal)

The G Man

I know on the new RAV4, the cruise control actually brakes to maintain speed while going down hill. I wonder if this is the same system.

IS0LD0UT

iTrader: (1)

My GS will do the same thing.

lexusdr

Same here.

GS3Tek

iTrader: (8)

This is normal and I read somewhere that people we're sort of complaining about this b/c you can't coast down the hill freely. I guess it's a mixed feeling

I'll try this some times

loflin

I/m confused.

yaro did NOT seem to imply he was using Cruise Control. The next post (Gman) brings up Cruise Control on the RAV4 and the next two said basically "same here".

Are we talking cruise control or not?

Without cruise control my GX WILL accelerate on a downhill run.

yaro, if you are not talking with Cruise Control, I would try your "experiment" again, to see if repeatable. Perhaps you were just at a point right between where the computer might call for a shift and going from coasting downhill and accelerating then tapping the brakes had it hold in the lower gear, and then engine braking kept you from accelerating above 40.

98Nav400

We have a "learning" type of ECU that control the transmission. It will guess how you are driving and when going down a hill, if it thinks that you want to hold speed it will downshift to make use of engine braking.

I go down a moderately steep hill @ 3 miles long with a 35 mph limit daily. If I start down the hill and let the vehicle freewheel it will and I will continue to gain speed; if I tap the brakes a couple of times, or apply them for a few seconds the vehicle will automatically downshift and hold a lower gear until I either stop, or accelerate long enough for the vehicle to upshift (it will be hesitant to upshift after it has gone into engine braking mode). I am used to it and able to start the engine braking at will. It simply lowers the gear, but doesn't seem to hold a speed by using the brakes in my experience.

Not a very good explanation but hopefully you get the idea.

sayadil

YES true ... The GX should go freely on a downhill unless u hold brakes for few secs.. then it maintains that speed throught out the steep... if you don't press brakes it should coast like any other vehicle.. i experience it pretty often goin towards the cottage and thinks its an amazing feature.

yaro1

That is what I meant. If I don't brake for a second or two, it coasts and accelerates as any normal car would. When I depress the brake about 30% down for a few seconds, the truck downshifts and holds the speed (not precisely like cruise control or DAC) while going downhill.

No, I do not mean crusie control. Next time I go down that hill (or another hill), I will try it again and post the results.

sayadil

Ok so thats just normal.. thats DAC working... i love all the little things GX does... i realize how important they r when i get into another car or even landcruiser.

V8_Fan

My LX also does this. The LX/LC's with the 5spd transmission ('03+) do this. The vehicle senses that you're going downhill so when you tap the brakes, it downshifts and holds that gear until you accelerate again. My LX is the first automatic transmission vehicle I've owned. I've avoided them in the past since all the previous automatics I've driven will accelerate regardless of one's braking while a manual 5spd transmission gives me much more precise control during a descent. The LX transmission, however, gives similar control as when driving a manual, so a for this feature. I also like the ability to specify the maximum gear from 5th (overdrive) all the way down to first (L)...pretty handy when driving in the mountains.