Using D3 For Engine Braking (Automatic)

I currently have a 2019 but may be getting a 2015 TRD automatic. I always use S Mode and D3 in my 2019 but the 2015 doesn’t have S Mode. How does using D3 in the 2015 work? Do I need to be at a certain speed or take my foot off the gas or slightly brake to move it from D to D3? What about once at the bottom of the hill - what do I need to do to move it back to regular D?

 

I can't say anything about how the 3rd gens work, but as someone who owns a 2015 and just finished towing a trailer 1k miles I can hopefully give some insight. As far as speed goes, I'd shift from D to D4 at no more than like 60mph. Same goes for shifting D4 to D3 to either engine brake or to keep RPMs up when starting a hill climb, probably don't make that shift above 55mph. Those are just general numbers, you'd figure out for yourself the real limits if you are really pushing it. Once you are done downshifting and you want it back in D (overdrive) just push the shifter back to D position. No slight braking needed, probably doesn't hurt to stay light on the throttle or let off while making the shift. Hope this helps, good luck.

 

The technical part is you just move shifter where it needs to be
To be honest I doubt it would let you do something to hurt it, but use some common sense, if it’s at 5k in 4th, don’t drop it into 3rd

 

You don't downshift to slow down. Use your brakes to slow down to the speed you want to drive then downshift to the best gear in order to maintain that speed with minimal brake usage. Or simply downshift to the gear you want before you start down an incline.

I drive a lot in the eastern Appalachians and have been all over the Rockies with and without a trailer. I've driven 30-40 miles coasting down grades using 2nd and 3rd gears to maintain a safe speed and only had to tap my brakes a handful of times. Tachometer stayed under 2500 rpm's.

 

I owned a 2010 for 8 years then upgraded to a 3rd gen. You can use the transmission exactly the same way as your 2019, except the shift gate is puzzle shaped.

Move the shifter D->4->3 at the same road speeds you'd shift D->S4->S3 on your 2019. If your downshift command would otherwise overrev the engine, the ECM simply delays the actual downshift until the truck dropped to a safe speed. To get back to 5th gear you'd have to move the shifter 3->4->D.

The 1GR sounds horrible above 3k lol but can be hammered at redline all day like any other Toyota truck engine, assuming of course the previous owner(s) kept up with maintenance.

 

It’s ok to stay on the gas while upshifting right? Mainly let off when downshifting? Or let off for both up or down?

 

So before the incline, I always do try to be in 3. But to downshift to 3 before the incline, would the correct way be to be gently pressing on the brake while dropping it down to 3? If I’m coasting gently with my foot on the gas, I shouldn’t downshift like that, correct? (Sorry, I’m still new to this, but 3rd works perfect going down the hills in my area).

 

Your transmission shifts thousands of times with you on the gas, brake or coasting
It does not matter

Also in a different truck, with a different engine and transmission, may not be the same gear choice

 

Strongly disagree. Granted you don't want to make large speed changes downshifting but coming down mountain passes bumping down a gear to slow down a bit is totally fine. I regularly tow a camper with a 3/4 chevy and I downshift all the time. Here in Colorado you need to, or you will lose your brakes.


I do agree with a manual transmission though, no need to wear the clutch when you can wear the brakes.

 

Don't over think it, it's not terribly complex. You don't want to go into too low a gear when you are traveling too fast and over rev, but I suspect the trans is built to not let you. The best way to learn is to putz around below 50mph and shift into the various gears, listen and feel the engine RPM. Don't let rev too much, and pay attention to roughly where your speed is for any given gear.

 

Feel free to stay on the gas just like if you're accelerating in normal automatic mode. You're merely giving a request to the ECM to authorize a higher gear. The ECM then shifts when it deems appropriate and manages the throttle cut (or throttle increase to avoid bogging) as needed.