S Mode & ECT Use for Mountain Driving

Yes and no. The point of downshifting on long downhills is so that you don't cook the brakes. Granted, it's difficult to cook a modern passenger brake on most roads when not hauling heavy. But its not impossible.

Climbing the hill and not hauling heavy - leave it in D.

Descending the hill - short or shallow: leave it in D. Long and steep and/or hauling heavy: Drop it to S4 or S3 and find a speed that the engine can maintain without using your brake like its a la-z-boy ottoman. It has to be really damn steep if you need to drop it to S2.

 

It reads different though, and almost contradicts itself when it mentions AI shift. Some things I’ve read say it shifts for you to stay in the appropriate gear. But the manual says I can select the gear and the Lower numbers are better for engine braking, so that’s why I’m curious about how to best use when going downhill bc it seems like I’d move it to S then have to hit the minus at least twice to get to 2 - but wouldn’t I likely be rolling faster speed wise than what 2 would be for? I guess I’ll just have to try it and hope I don’t blow anything up.

 

Yeah I thought S mode was like "manual mode" when I first got mine too (because it was in my Volvo that I had previously).
In our trucks, if you put it in S - it still shifts on its own, but won't go into the highest gear (I think - or maybe the highest two gears)...may depend on how fast you're going.
If i were towing, though, I'd definitely put it in S, and try to keep it below 70mph.

 

You won't blow anything up. If you try to drop to 2 or 1 and the computer thinks it's too harsh, it will refuse the command and give you a quiet double-beep. The double beep is Toyota-speak for "you're rolling too fast for that action holmes."


And for clarity, S mode means it locks out n+1 gears. If you are in S4 for example it will shift the transmission like normal at points 1-4, but will not upshift to points 5 and 6.

 

it will not go past whenever gear you have selected in S Mode. if you select 2 it will not go past 2,etc.

when you move over to S mode it defaults to 4 and you then adjust to whatever gear you desire. if i am going up a hill i select 3 then when i am at the top of the hill i put it back to D.

 

If you can find me a single post of someone cooking their brakes in an automatic going downhill on a grade not steep enough to justify 4LO, I'll buy you a beer next time you're out wheeling in CA.

 

I'll give you one of the most common examples. Pikes Peak, speed limit at a scant 20 mph. There's a checkpoint halfway down the hill where all cars are required to stop and take a temperature reading on the brakes. If it's over 300 they'll pull you over, you get to retest every 15 minutes.

After getting the "dang, 155, good job" from the ranger, I had to ask how many cars she fails on an average day. "About half" was the response.



I use the lower gears frequently in the Rockies, 90% it's with my camper in tow. It really only takes one hard brake with the trailer before the pedal gets spongy from heat. I've done it myself on freeway off-ramps.

On the days I'm knocking around without the trailer, I usually don't drop gears unless it's a mile long grade 10 or worse. Even then, if you're pulse braking more than once every 60 seconds or so, drop the gear, save your shoes.

 

A perfect example of when to be in 4LO, though. Mauna Kea in HI is the same except that they literally won't let anyone up who doesn't have a low range gear.

 

That doesn't make sense to me. Why put unnecessary stress on the CVs by binding them on paved switchbacks, when S2 is right there and available?

 

Thanks everyone for all the responses.

From what I’m gathering, I “think” moving it over to S 4 and just leaving it there would work for what I need - both uphill and downhill through Shenandoah National Park, correct? Do NOT use ECT to get uphill, mainly for towing?

I know S 4 means it won’t go higher than 4 on its own - but does it also downshift on its on if I automatically drop my speed but don’t manually click it down using the minus button? Like if it defaults to 4 and I leave it there but slow my speed dramatically, does it drop down to 2 or 3 and then the display updates to reflect that?

And lastly - when at the top or bottom of the hill, just kick it back over to D on the fly? No need to stop to put in or take out of S?

Anywho - I believe I have it. It seems like S4 would work for going up hills and engine braking going down. S 2 would be for extremely steep. But seems like S 3 could be in play. I’m just confused bc old things I read from previous vehicles said to use 2 or LO on steep hills. Just confirming if 3 or 4 would be best for my situation.

 

Yeah - just stick that sucker in S4 and don't think about it. Pop it out when you're done with the hills (on the fly). In fact, you could very much just leave it in regular old D and be fine. It'll just shift up higher than 4 if it gets to that point (and maybe downshift a bit less aggressively to assist with braking).

 

What happens if you exceed the max speed for 4th gear? Will it then upshift to 5? Or does it somehow limit your speed to what you set it at regardless of how much you press the pedal?

 

It won't upshift beyond selected gear unless you go beyond redline on engine rpms. It's possible to do that in S1-3, but you'd basically have to be doing it on purpose.

 

So it’s possible in S1-3 but not S4? I guess from what I’m understanding is - you move it over and whatever it is set at (S4 for example) - it will downshift on its own if you go slower but it won’t go any higher than S4. Correct? So if I choose S4 but slow dramatically, it could work itself down to 1 or 2 (and hopefully reflect that in the display), but if I speed up and mash it, it won’t go higher than S4? It wouldn’t auto shift to S5 to protect itself?

 

No.

It's not possible because from very fuzzy memory, 6000 rpm in 4th gear would be 140-ish mph. It'll be just under 100 mph in 3rd, and some people have hit well over 60 in 2nd.

Like I said, you'd have to be purposefully trying to break your truck for it to override S mode.

 

Does it auto shift down though? If I move it over to S4 but go very slow, will it drop it to 2 or 3? Basically, what happens if you do significantly less RPMs than the highest gear allows?

 

Yes, it's an automatic transmission whether in drive or in S mode. S just limits how far it will upshift.

 

What if I’m doing 65mph and kick it over to S mode and it defaults to S 4. Will I feel any jolt or anything? Isn’t S 4 for up to 55mph?

 

Have you never driven an automobile before? Take it out on the road and experiment with it and maybe you'll learn how it works. It ain't made out of tissue paper, you aren't gonna blow it up.

Well, not right away at least. Probably.

 

There aren’t hard mph limits. It will kick up your rpms, but as rock lobster said you won’t even be close to redline at 65mph.
To echo what’s been said; it isn’t complicated and you’re overthinking it. Just practice and you’ll get the hang of it in a few miles. There’s not really a way to mess it up. Worst thing that’s going to happen is your mpgs will drop from higher rpms.

No need to use it going uphill unless you’re towing.
“AI-SHIFT” is D. S-mode disables it