Gears and RPMs 2017 Highlander

[Scotttbaum]

Heading over the mountains for first time. TV is 2017 Highlander with 5000LBS capacity. What gear should be used uphill and down? What is a good RPM range to keep while doing either? Should I use automatic settings for flat grade or stay in a specific gear range?

[Brian B-P]

What does the owner's manual say?

[gbaglo]

Originally Posted by Brian B-P

What does the owner's manual say?

My owner's manual refers you to page 89, which refers you to page 103, which refers you to page 481. Irritates me no end. Still don't know what Toyota calls the rear hatch/door or if it will automatically stop opening, and retract if it detects cross-traffic.

[Scotttbaum]

It only says to not go past 6 for eight speed model and 4 for 6 speed. nothing on what to use on grade or what rpm to maintain.

[Iowa Dave]

Originally Posted by gbaglo

My owner's manual refers you to page 89, which refers you to page 103, which refers you to page 481. Irritates me no end. Still don't know what Toyota calls the rear hatch/door or if it will automatically stop opening, and retract if it detects cross-traffic.

If you put your arm in the way of the rear hatch closing it will stop before it hurts. Try it

I tow in 6 out of 8 on the flat. Uphill or downhill I am comfortable buzzing the engine to 5,500 RPM. Downhill I’ll downshift on the decline usually 5-4-3 and stay off the tow vehicle brakes. Real steep and for short distances 5-4-3-2. Uphill usually 5-4 will do about anything to 8%.
Good oil, (Mobile 1) is a must. Let those ponies run they like to feel the wind.
Iowa Dave

[Brian B-P]

Originally Posted by Scotttbaum

It only says to not go past 6 for eight speed model and 4 for 6 speed.

The currently published owner's manual for the 2017 Toyota Highlander (non-hybrid) does not say that.

In the trailer towing section, one of the hints is:

● To maintain engine braking efficiency and charging system performance when using engine braking, do not put the transmission in D. If in the S mode, the transmission shift range position must be in 6 (8-speed models) or 4 (6-speed models) or lower.

Notice "when using engine braking": if you don't need to use the engine to keep the speed from going too high while descending a hill, this doesn't apply.

Another hint is:

● Instability happens more frequently when descending steep or long downhill grades. Before descending, slow down and downshift. Do not make sudden downshifts while descending steep or long downhill grades.

so if you're going to shift to S6 or anything else other then D, they're saying to do it before starting down the grade. These two points are the only mention of the transmission (or engine speed) in the towing section.

The Automatic transmission section starts on page 227. It explains that

Selecting shift ranges using S mode restricts the upper limit of the possible gear ranges, controls engine braking force, and prevents unnecessary upshifting.

This is how automatic shifters conventionally work. So if you never want to think about shifting while driving, put it in S mode and select "6": the transmission will pick the most appropriate gear, but never go higher than 6th (it won't use 7th or 8th). If you need more engine braking, go lower (as Dave suggested) only as long as you need the braking. There is no mention of trailer towing in the Automatic transmission section, so nothing else you need to worry about. For possibly better fuel economy and less engine noise, use "D" and shift to S6 only for engine braking.

Originally Posted by Scotttbaum

nothing on what to use on grade or what rpm to maintain.

The vehicle has an automatic transmission - a manual isn't even available. They don't expect, need, or even want the driver to try to determine the best engine speed for performance or economy; there is no single "correct" or optimal engine speed for all conditions.

[Brian B-P]

Originally Posted by gbaglo

My owner's manual refers you to page 89, which refers you to page 103, which refers you to page 481. Irritates me no end. Still don't know what Toyota calls the rear hatch/door or if it will automatically stop opening, and retract if it detects cross-traffic.

In the currently published 2020 Highlander manual none of those pages are related to shifting the transmission, so this must all be about the hatch or something else irrelevant. The information needed to answer the question about "Gears and RPMs" while towing is in the Automatic transmission and Trailer towing sections, where it belongs.

[gbaglo]

What is 'S' mode? I have 'M' ( manual ) and 'D'. And, then there is a button for Eco, Sport and Normal ( default to Eco ).

[Brian B-P]

Originally Posted by gbaglo

What is 'S' mode? I have 'M' ( manual ) and 'D'. And, then there is a button for Eco, Sport and Normal ( default to Eco ).

You also have a 2020.

In the 2017, if you move the lever from "D" (Drive) to "S" (Sport), you can then select the highest gear which will be used by pushing the lever to the "+" and "-" positions. It's exactly like the "-2-1" or "-2-L" selections on old three-speed automatic; they just don't want the shifter for a 8-speed to have P-R-N-D-7-6-5-4-3-2-1 positions, because that's too many.

In the 2020, "M" (Manual") mode replaces the old "S" (Sport) mode, but it's much closer to truly manual control of the transmission:

The gear changes once every time the shift lever or paddle shift switch is operated.
The selected gear, from M1 to M8, will be fixed and displayed on the meters.
When in the M position, the gear will not change unless the shift lever is operated.

The transmission control computer does take over and force gear changes if the driver really messes up by selecting a gear ratio which would stall the engine or spin it to destructive speeds. This mode is nearly pointless, because it requires the driver to decide on every gear change. The intent is clearly to let the transmission logic do its job; the driver should never need to use M mode.

The 2020 manual has the same towing hints regarding gear selection as the 2017 manual. The bit about getting shifting done before descending is essentially antiquated nonsense repeated in all Toyota towing sections, and "M" replaces "S" in the tip about staying in 6 or below with the 8-speed... but with the 2020's M mode, you're stuck doing all of the shifting yourself, which is a mostly unproductive annoyance.

[Mike G]

In my 2008 HL, S stood for SelectShift. It worked the same, but with only 5 gears.


I used to climb most grades in the 3500-4200 RPM range, mainly because I have never liked the sound of higher revs but I wanted the extra torque that the engine produces at higher RPM. I'd shift down to 3rd, occasionally 2nd. I never tried to push the drive train hard, such as charging up the grades at 55-65 mph; even if I'd wanted to do that, the transmission temp light might have come on (as it was doing more often before I sold it at 185K on the odometer).

[Tom&Joan]

This is too complicated for me! Oh for a good old standard shift. Never have to even think about shifting, you just do it. The only problem is the high ratio in reverse for most of them. It forces you to abuse the clutch when backing up. Even some trannys in larger trucks are deficient in this regard. In pickups a low range 2wd is helpful. I guess it is obvious I must admit, some of the designs are "foreign" to me.

[Scotttbaum]

Thanks all! All points are good and I feel a bit more comfortable now. You have confirmed my thoughts and I will venture forth with a little more confidence😎. Hope to see you all out there soon.

[Brian B-P]

Originally Posted by Tom&Joan

This is too complicated for me! Oh for a good old standard shift. Never have to even think about shifting, you just do it.

The current Highlander works that way in Manual - you just shift yourself - a lot with 8 ratios - without needing a clutch and with the computer saving you from any serious mistakes.

Originally Posted by Tom&Joan

The only problem is the high ratio in reverse for most of them. It forces you to abuse the clutch when backing up. Even some trannys in larger trucks are deficient in this regard. In pickups a low range 2wd is helpful.

Low range is typically not available in 2WD mode. just 2-Hi, 4-Hi, 4-Lo, and various modes that automatically engage 4WD but only use high range.