Is there any reason NOT to downshift the Toyota A/T when you want a little bit of engine brake, just as if you had a manual? Can an automatic tranny expert explain what kind of clutches or planetaries are being affected when you do this?

 

Hopefully not. I do it all the time.

 

I don't think so, I do it all the time in the mountains.

 

I have been doing this in the winter. I keep it in 2nd sometimes with o/d off so i get engine braking when i let the foot off the gas..keeps down the uncertainty of braking in bad conditions. the manual goes through the procedures for engine braking so it should be fine if you do it properly.

 

I downshift too, I like it better than heating up the brakes.

 

i do it too =] i like to hear the engine rev instead of squeaky brakes

 

Towing with stock 4runner brakes you almost have to downshift and engine brake.

 

Thats one of the reasons they have more than just D and R on your tranny. Some of these guys who are on the stick shift wagon don't believe you can shift an auto into first or second when climbing or descending a hill or off road.
I live on top of a mountain and drive mountain roads every day and I'm always down shifting or up shifting in and out of O/D too. Been doing it for years and my 01 tranny is like new. I may be wrong but I think it does the tranny good to go through all the gears once in a while even for flat landers.
Some people never use anything but D and R.

 

In my humble opinion (and also some pretty good mechanics I have known), downshifting for braking purposes should be kept at a minimum. It really should only be done on steep declines to keep the brakes from over-heating and failing (what it was designed for). This goes for manuals as well, but even more so with automatics.
It places unneeded strain on both the engine and tranny.
Brakes are cheap and easy to repair, engines and transmissions are not.


My 2 cents...

 

I agree with that to an extent...

As long as your RPM's aren't revving really high, I think it should be okay.

 

I've done it to 2nd at 65 MPH. haha. Fun stuff.

Nate

 

Thats a really good idea.

 

the main thing is to know when to shift and pay attention to the tach. downshifting or letting off the gas when the rpms are too high will cause too sudden of a brakeing effect and could put you in an even worse handling situation

 

No, THAT's a really good idea

 

The tach. was at about 4300. Sounded pretty smooth though.

Nate

 

IIRC the computer won't let you manually shift the auto into a lower gear if the speed is too fast for it.

 

The concept of adjusting your gear ratio for load/speed/rpm/grade is a given. Being too lazy to read the FSM, what I am questioning is whether the additional shifting, down and up, places additional wear on clutches inside the transmission, so to shorten the working life of the unit.
I love the way the Toyota A/T responds to my commands, many other makes of cars don't respond well, or at all, to changes at the shifter while you are underway.

Also, I agree that brakes are cheaper to change than drivetrain components... there's a philosophical tension there...

but... digressing...

One day I might drive my first gen 4Runner with a 5-speed...

.

Another day, when I feel like driving something RED
I'll take the 96 4Runner, which has the automatic...




I'll use the O/D cancel to decelerate from say, 60 to 45 coming to an exit ramp off the Interstate... then drop from D to 2 at 45 as I go around the curve of the ramp... its unnecessary.... but fun.

 

I think the biggest concern with using the engine braking in the auto is to just make sure the trans fluid temp is okay. As far as the clutches are concerned the torque converter does a pretty good job at absorbing the shock on a hard downshift and the computer does a pretty good job.

Using complete off throttle engine braking will usually make the injectors cycle drop so the MPG for that point in time will be very good since the motor is essentially running on gravity and momentum and everything from temps, oil pressure, to efficiency go in its favor.
Just have to make sure the crankcase ventilation is in good shape b/c on a long hill thats a good bit of vacuum to pull for an extended time on a bad PCV system.


misterzee nice red 3rd Gen... don't see that many around.

 

Thanks for that input RacerX, and the compliment :-). The Red Baron sports an elocker as well. My other projects that I'm excited about is the red 85 SR5 pictured, and, not pictured yet, my 'new' red 89 Pickup 4x4 Ex Cab (some people are now thinking... this guy has a problem.... LOL)

 

rev it up at a stop light then.