I really need someones help on this. I'm still noobish when I comes to shifting with an Automatic with an Manual option.

I was driving along today getting the hang with this feature when a car in front of me just braked to a stop fast. I was in 5th gear going around 45mph when i saw this while driving in Manual mode. Now, I'm used to Automatic so I stepped on the brake to keep from crashing into this car, but when i did I didn't stop smoothly. My RX-8 like stuttered to a stop and I felt and heard like something was grinding. I would say it was because I didn't get to down shift.

I know with in a high gear and you suddendly need to step on the brakes, you press in the clutch and brake, then just shift down to 1st when you need to accelerate again, but what about when your in a Semi-Manual 8 and need to brake hard? It doesn't have a clutch pedal so what do you do so you can stop fast correctly from a high gear in Manual mode (in an Automatic car with the option) without that grinding and stop smoothly? Do i just quickly tapping the down shifter or quickly switch to Automatic mode and brake?

It was honestly kinda scary because I didn't know if I would stop in time because my Mazda had a rough time stopping =(

 

You are fine. It's called ABS. (Antilock Braking System) Your wheels were skidding and locking up.

Read this. ABS

 

You know i was reading about it and I thought about it and I think your right =)

but the thing is that it usually only happens when I'm using my paddle shifters, i break the same amount with I don't use it and my car doesn't kick in with the ABS so sensitively when I don't shift down =P

Very weird!

 

Your paddle shifters have nothing to do with the way the car brakes. Unless your down shifting and using the engine compression as a braking mechanism to slow the car down. But that's a different story.

ABS does not know Manual mode from Automatic mode. And why are you always stopping so fast that the ABS comes on? The only time ABS will engage is when the tires lock up during braking.

Do this,,
Find an empty safe road. Get to about 40 mph and STOMP on the brake pedal. Do not let up until the car stops. Try this in both shifting modes.
Then tell me what differences you find.
No difference will be the result.

 

Automatics do NOT have engine braking abilities, for the most part, so if you hit the brakes hard, regardless of what "gear" you're in, it doesn't matter to the transmission one little bit.

Think about it like this. A manual transmission is like using free-weights. Free weights offer resistance when you pick them up, AND when you put them down. An automatic is like the gimmicky one-directional weight machines of the 90s; they offer resistance when you push on them, but no resistance when you're setting back down.

The setting down is comparable to engine braking; an automatic doesn't have that ability. So, the automatic transmission isn't going to cause the engine to sputter as you come to a stop, if it hasn't been downshifted, because it doesn't offer resistance to the engine.

IF you were having some jerky issues when braking hard in an auto, then you've potentially got some brake issues (if it wasn't just the ABS pulsing). Warped rotors, worn pads, sticking calipers, low brake fluid, etc. can all cause what you're talking about. Take your car in to have it's brake system checked out, if you can't do that yourself, and you should be good to go.

This has nothing to do with the transmission in your car, nor your technique.

 

Have you ever driven an AT RX8?

 

I said "for the most part"... The only "engine braking" that happens w/ an auto is it revs up, and the engine wants to stop revving when you're off the gas, so yeah, you'll get a little bit, but it's effect is DRASTICALLY reduced by the automatic transmission; that's part of how they work... The torque convertor generally doubles the amount of torque in 1 direction (under load), but does nothing when it's not under load. So engine braking is practically non-existant compared to a manual transmission in the same car.

But no, I don't drive an Auto RX8. But I still don't see how/where a grinding sound could come from the tranny when braking; it sounds like a brake issue.

 

Funny but when I down shift my AT the car slows down just like a MT. Only time it doesn't is when the engine rpm's drop below the stall speed of the torque converter As long as the Torque Converter is spinning above the stall speed it is connecting the engine directly to the drive train.
So how can it not slow the car down as with the MT?

 

I was driving a lot in San Francisco last weekend, and rather than breaking on every down hill, I just used the manual shift, down shift, and slowed down. So you can use the transmission to break, even with an auto.

 

Yes you can. And the new 6 speed AT will do it for you if your in Drive.

 

maybe i need to let you drive my AT 8 xD


I agree though, because my AT does slow down when i down shift too.
Unless I shift toooo low then my 8 doesn't let me and slaps my hand away from the paddles haha


but i will definately try to do that test to experiment with the auto and manual

 

Braking and downshifting help slow down, I remember having a manual 1983 Civic and i down shifted under hard braking to help drop speed quickly. I have the A/T 8 and I drive with the Manual mode on all the time and I downshift to slow down ALL the time. I went 3 yrs without having to change brake pads. I got my 8 in 2008, and I just change my pads last month.