Down shifting an automatic

As the title reads, I got a lot of highway and long country road driving done yesterday, and came across a few long downhill gradients. Do you guys think it’s wise to downshift to say 3 or even 2 if moving traffic permits? Will I hurt the transmission, should I just say “that’s what breaks are for” and not worry? Before anyone thinks I haven’t read the manual, I have the pages with 4lo and locking differential and the like all book marked. I still haven’t used the downhill assist button can’t quite figure out if that’s just used for when trailering . Thanks in advance guys and I hope this doesn’t sound like a dilly qurstion.

 

Let the automatic transmission shift gears, and the brakes brake the vehicle.

I'm also pretty sure that the downhill assist is for OffRoad use. But I'm not entirely sure.

 

Thank you for your time dustsorm. I should have mentioned 2015 Off road. first Toyota, not my first truck though, just came out of a 2005 GMC Sierra, great truck didn't owe me a dime. Ive had my eye on Tacomas for quite some time

 

I too have a 15 off road. I have read the manual several times. I believe the down hill assist is for off road applications, at least that what I gather from the manual. I recently drove from upstate ny to Florida and back and I just let the tranny do its thing. I came over from a 2500 ram miss tow haul mode for hills but love my tacoma. Just my 2 cents.

 

I tend to downshift when braking to a complete stop. Never an issue

Downshifting when traveling on a downward gradient? I've never done it personally, but if you were so inclined to do so, I'd make sure the RPM's were reasonable and I didn't do anything dumb. Like others have said, I'd likely let the brakes and transmission do their jobs, mostly out of laziness and comfort.

 

I sometimes shift from 'D' to '4' on my 2015 when exiting a freeway or descending a long hill, but not always. Like DustStorm says, it's fine to just let the truck do what it's designed to do...

 

If you are descending a grade that has signage stating 'trucks use lower gear', it's no problem to do so.

Sure, it's for semis, but the idea is to not overheat (and lose) their brakes. No reason not to do the same in any other vehicle. You'll easily tell when engine braking has exceeded its usefulness and it's time to upshift again.

In city traffic engine braking is a waste of time, auto or manual. Even in performance driving schools for autox and road course events you'll be taught that you only downshift to accelerate out of a turn, not to slow going into the turn. Brakes are cheap. Valve trains are not. Rev limiters do not function on downshifts (more a potential problem on a manual missed slot than on an auto).

 

What is the speed limit on this road ?

 

downhill assist only works in 4lo. when you are going down hill, it allows you to take your foot off of the brake and it keeps you at a crawl.

I only downshift in my truck (automatic trans) when I am towing. keeping it in a lower gear when I need the power to climb a hill or when I need to keep the speed down when descending a hill. in regular city driving, I keep it in D.

 

Please use the transmission in a lower gear when ever possible on downgrades. It won't hurt a thing, is much safer, and will save your brakes and rotors. It may not be necessary on slight slopes, but in mountains where you may drive downhill for miles you'll burn up your brakes and warp rotors within just a few miles.

 

Long downhill engine braking is one of the main reasons why lower gears are selectable in automatic transmissions. It wont hurt anything, just be reasonable with which gear you choose.

Also, all autos that I have ever driven (including my first car, a 1987 Chevy Celebrity) will not go into lower gears at specific speeds, presumably to protect engine and transmission from damage.

 

Right^^^. If your in OD and doing 55mph you don't want to drop it down to 3rd gear. In most vehicles the electronics won't let the transmission downshift that much anyway until the speed drops some. But you can drop down one gear at a time and use your brakes to get to a safe speed. The goal is to be able to come down off a mountain grade and never have to touch your brakes. Select a gear that allows you to do that. Often as the steepness of the grade changes I'll upshift, then drop back down as needed. I've driven 30 miles on downgrades before and never touched my brakes. You can always pinpoint the flat landers cars in towns near mountains without looking at the plates. You can smell their brakes burning from 1/2 mile away.

 

Dagosa if I remember Id say 50 55 ish. I want to thank all you guys for taking the time to reply and help me out by sharing your experiences and info. I appreciate it I really do. Like I mentioned this is my first Tacoma and don't want to screw something up. One of my biggest pet pevves is doing something wrong then having someone say " you never do that everybody knows THAT"

 

Agree with Marshall R.

If the downgrade is such that you are constantly on your brakes to control your speed and/or to keep your vehicle within a reasonable level of control, then downshift and let your gears work for you. You'll intuitively know it's time to upshift when your chosen gear starts to restrict your forward momentum, as opposed to keeping it in check.

Last summer we took a drive down to Lake Placid and we drove up to the top of Whiteface Mountain to do a bit of a hike, take some pictures, etc. Coming back down I think I touched the brakes twice. The rest of the time I relied on a lower gear. If I had not done that, my brakes would've been destroyed.

 

Yes some do down shift I believe the Taco has to have a brake application first then it will drop to a lower gear. I was in a Ford Explorer yesterday on the highway with the cruse on it automatically down shifted to maintain the fixed speed going downhill I don’t know if the Taco will do the same or not because my 6 spd manual just stays right where it is! So the answer to the question no it won’t hurt it to down shift it within reason meaning down yank it into low at 70!

 

Totally agree with Marshall R and NMG. Treat the auto trans like a manual on long downhills, so your speed doesn't increase when no throttle is required. Save your brakes for an emergency. Camped once on Monarch Pass, USFS campground about 100 yards off the highway. Saw an 18-wheeler with flames coming off the brakes, and when wind was right the primary smell was overheated brakes just from cars. Doesn't take but a few miles of over 4% grade to completely fade brakes used inappropriately. Also you can turn on your A/C to add a little extra drag downhill. The "trucks use lower gear" signs are a good indicator of a steep/long grade, along with the "emergency/runaway truck ramp" signs.

 

Anybody who recommends not downshifting and letting the brakes do all the work on a downgrade either lives where it's flat or is contributing heavily to their chosen brake mechanics retirement fund lol

 

I live on a hill and utilize the engine braking everyday. I throw it into 4 at the top and it maintains a consistent speed til the bottom. I am not going to ride my brakes all the way down the hill like I see most people in front of me do. Even worse are the guys that throw it into neutral and work the brakes even harder or are flying down the hill at unsafe speeds.

 

Its totally fine

 

The tranny will automatically downshift on declines when I hit the brakes hard. Sometimes it'll go down two gears which is nice so I'm not riding the brakes. Especially helpful when I am towing my ~1200lb boat/trailer.