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Is it ok to downshift in an automatic to engine brake and help slow down the car? Does anyone know of any possible negative effects this could have? Thanks.
 

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I do it all the time...so long as you rev match I don't see how it could be any worse than doing it in a manual. The one thing I've heard is that manually shifting all the time can put some heat on your tranny, so it might be a good idea to switch to synthetic tranny oil for sure, and get a tranny cooler to be as safe as possible.
 

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its definitely going to cause more wear than normal driving. syn fluid may help, as well as a cooler, but it just wasn't designed to do that on a consistant basis in DTD driving. personally, if it were my auto, i wouldn't. but i don't think you'll see any major effects any time soon.

dR
 

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If it were my auto (and I do have one) then I would, and do. I have recently installed a cooler (after 40k miles) mainly because I will be racing more often. Driving the car this way stock is OK.

Automatics are designed to be manually downshifted, just as are manuals. Actually it is 'safer' in the auto because it won't let you over rev the engine when downshifting. If you select a lower gear at too high a speed the valve body will not shift until the speed is at a safe level.

Do this. Run the car at 65 mph. Select second gear. The car will not shift. Slow down. When the car reaches about 60 the tranny will shift into second gear. You can do the same thing from 2nd to 1st (at about 20 mph).

Once you get the hang of where the shift points are you can determine when to select the gear you want. I usually downshift to second at 50 and rarely downshift manually into first (unless I want to exit a very slow corner fast).

You do not need to 'rev match' the engine. It does make you feel more like you are driving a manual, and probably reduces wear slightly (like double clutching a manual), but, it is not needed (I never do it in cars and light trucks). Yes, I have driven autos a lot (30 years and over a million miles) and have never had one with a problem when driving this way.
 

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Yes, it's OK. Look in your owners manual and see if it doesn't recommend downshifting from 4th to 3rd on a steep grade etc. my wifes OB owners manual did....

boxman
 

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I believe technically the transmission does have fuzzy logic for steep grades.

For just slowing down....unless you're willing to perform more maintenance (changing the ATF more often)....just use the brakes.

It's something I only do to rental cars.
 

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I think if Subaru didn't intend you to manual shift they wouldn't have that nice gated (?) arrangement that allows you to hit each gear without looking. I have been practicing shifting mine and haven't yet gotten it completely right yet. Also if I understand right, the auto will upshift to the next gear if you go to redline. I tried this out at the dragstrip (running in 3rd) and it seemed to work ok.

Dale
 

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Downshifting will result in a shorter tranny life, increased wear and tear etc.

It's much cheaper to replace your brakes than replace an AT AWD Tranny.

Coolers are great if you plan to do track events. I'm currently putting one into my SVX.

I raced my XT6 AT in auto-x quite successfully I might add.

I have tons of experience with the 4EAT trannies in subies so ask away...

-mike
 

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aahhh downshifting...so fun

:( yes i have an auto.....i dun know why but yes i have one. i regret it now. engine braking helps you to slow down so quickly. it's just a shame that down shifting with the auto tranny just tears that thing up.

:D i don't believe you can sucessfully "double clutch" or rev match with the auto tranny. hehe b/c you don't have a clutch. i've tried it myself.

with the timing and all....i think i've practiced it so much my tranny is going to die on me sometime. with the timing i've got it down pretty much. if i'm going 70 on the off ramp i'll down shift to 3rd half way to the end then i move the shifter in front of 2nd. before i apply the brakes i down shift to 2nd.

the shift into 2nd usually takes less than half a second so....i shift then brake almost simultaneously. seems to work better that way.
 

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Verdugo said:
I do it all the time...so long as you rev match I don't see how it could be any worse than doing it in a manual.
question: How do you rev match an AT? I'm not trying to start a fight or anything; I really am curious how to do this... I always thought you needed the box in neutral to get the engine revs up to the tranny revs...:confused:
 

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dookiebob said:


question: How do you rev match an AT? I'm not trying to start a fight or anything; I really am curious how to do this... I always thought you needed the box in neutral to get the engine revs up to the tranny revs...:confused:
It's actually not too complicated...there's a little delay when you shift gears manually...say from 3rd to 2nd...enough of a delay where you can rev it up a little. This is delay is pretty much neutral. You have to time it right, but once you got it, it comes real naturally. I do it a lot when there's a green left turn...rev match from 3rd to 2nd to make sure it doesn't shift up for you in the middle of the turn, so you it won't be jerky :)
 

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Paisan said:
Downshifting will result in a shorter tranny life, increased wear and tear etc.

It's much cheaper to replace your brakes than replace an AT AWD Tranny.

Coolers are great if you plan to do track events. I'm currently putting one into my SVX.

I raced my XT6 AT in auto-x quite successfully I might add.

I have tons of experience with the 4EAT trannies in subies so ask away...

-mike
Amen. I'd much rather replace brake pads than frictions and overrun clutches...

Personally, I think that EVERY automatic needs an external cooler, and it's mandatory if you're planning on doing brake-torque launches. I have a trans temp gauge in the pod on my Syclone, and it's alarming how fast the trans fluid temp heats up when you're launching, even with a big external cooler.
 

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I have an external cooler and plan to install it soon. Doesn't the WRX have a transmission cooler built into the radiator? The reason that I have this impression is that the various instructions people have posted for the installation of the external cooler say that you should tap into the ATF fluid lines as they exit the radiator.

Also for those of you that have installed the cooler, which side of the radiator do they come out. I have seen instructions that say passenger side (right) but I can't see any lines coming out on that side. I do see two lines on the drivers side at the bottom though. Are those the ones?

Dale
 

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iceNine said:
I have an external cooler and plan to install it soon. Doesn't the WRX have a transmission cooler built into the radiator? The reason that I have this impression is that the various instructions people have posted for the installation of the external cooler say that you should tap into the ATF fluid lines as they exit the radiator.

Also for those of you that have installed the cooler, which side of the radiator do they come out. I have seen instructions that say passenger side (right) but I can't see any lines coming out on that side. I do see two lines on the drivers side at the bottom though. Are those the ones?

Dale
Yah, there's an integral heat exchanger for the transmission fluid built into the radiator. But you want the extra capacity an external cooler gives you, and you want it to be added in series, AFTER the built-in cooler. Otherwise, you'll just end up warming the fluid back up before it returns to the transmission.

I had my cooler tapped in to the line on the right side of the radiator, but I had a hard time getting everything tidy and well-connected. So I ended up re-routing the cooler lines to tap in on the driver's side where the stock hose connects to the hard lines. It was a LOT easier this way, and the hose clamps were positioned in a much better place to keep an eye out for leaks.

If you look down in there and can't see what I'm talking about, let me know and I'll take a picture of my installation and post it.
 

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While not a WRX, there are pics of the in-progress install on my SVX. Since there is little room in front of the condenser for the AC we had to put it behind the AC in front of the Radiator. Also check and see which fan is the "master" fan and which only comes on when your AC kicks in. For the SVX it's the passenger side. We were having a hard time getting the hoses routed as well and wound up making up hard lines from the cooler to the originals. You also should put in a filter while you are putting in the cooler since particles can clog up the works and render your coolers useless. Pics here http://isuzu-suvs.com/svx

-mike
 

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As some of you may know, several cars use the 4EAT. My parents' '93 Mazda MPV minivan is one of the vehicles that uses the 4EAT. I was doing doughnuts in the dirt with it when I chipped a gear. A shop rebuilt it and I was engine braking and manually shifting (Before I figured out I could revmatch) and it toasted the transmission into submission. I popped it and not enough hydraulic pressure was available to push the clutches in place for second fourth or reverse.

So, GET A TRANNY COOLER. It's 100% absolutely ESSENTIAL to the longetivity of the 4EAT.
 

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as long as its not to huge of a rev differance, engine braking is actually fine.. Make sure you have a tranny cooler for the long run, and learn how to rev match!!


Rob
 

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Revmatching with a 4EAT isnt as hard as say with a BMW steptronic or the Acura TL/CL Type-S 5-speed. You just pop it into a lower gear, and prod the gas before engine braking comes in. Too much and the car jerks, too little and you'll feel it lurch forward, but if you do it just right, it feels and sounds good.
 
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