Automatic trans driving tips?

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Oct 11, 2002
Colorado Springs
I've got an auto in my 02 Corolla; up untill now I've always had manual trannies. I LOVE THE AUTO. Anyways, I read here all the time that downshifting an auto is a no-no. Well, in Colorado, it's kind of unavoidable, especially in the mountains; unless you like losing your brakes and scraping yourself off the bottom of a ravine. Is it really that bad to downshift an auto manually? Seems like it's no different than slamming the gas and having it downshift automatically. My Corolla has an overdrive on/off botton on the shifter and I've been using that frequently to help slow down and maintain speed while descending hills. Am I slowly killing the tranny by doing this?
It is fine to use it for engine braking. ATF overheats easily with excessive engine braking so I would recommend doing more frequently ATF changes. Or install an additional ATF cooler.
Why does ATF get hotter when engine braking? Just higher sustained rpms? I usually try and keep it at 2K or under when downshifting.
It's pretty much the shift getting in gear, most cars don't hop into gear quickly while downshifting, but instead slowly ramp-up the RPM's creating a great deal of heat and clutch-pack wear. I've seen some people toss their car into first gear at 40 mph, and the rpm's take about 2 seconds to go from under 2k rpm's to 5,000 rpm's which has got to be bad. You say that you keep it under 2k RPM when downshifting, that should be pretty good. Just as long as it doesn't seem to slowly ramp up the speed when you downshift. Whenever I downshift, I will usually slow down to the speed that it would usually upshift out of the next gear beyond what I am trying to get into when I am accelerating at a very slow speed, so for example I'll put it in first gear after I am down 20mph or less, and second gear I'll be going less than 40mph. I've found out that when downshifting if I give it a little bit of gas until it is in the lower gear, it will reduce any 'ramp-up' in rpm and make the shift a little easier on the transmission. If there is a stop sign before going downhill, as in half of the hills I go down, I will put it in the lower gear ahead of time. Most people would recommend shorter intervals on ATF when it is used in mountainous ranges and some people on these forums might mention that using synthetic ATF could provide better protection and possibly longer fluid life as well.
Question, Drew99GT, would you rather replace front brake pads and rotors more often or face an even more expensive automatic transaxle rebuild because the friction facings went south prematurely from implementing engine braking?
Worst part about downshifting most automatics is the lever is not made for it and you can easily overshoot. Driving an automatic. First of all, get a shift kit to firm up the shifts. Second, fill it with Redline ATF. Now if my main ride had to be an automatic I would be tempted to go full manual valve body. [Big Grin]
Originally posted by Ray H: Question, Drew99GT, would you rather replace front brake pads and rotors more often or face an even more expensive automatic transaxle rebuild because the friction facings went south prematurely from implementing engine braking?
When I say that downshifting is like a necessity on some of the drives I take, I mean it! I drive over a pass called Hoosier pass very often; it's about a 3,000 foot elevation drop, maybe more. You'd overheat the brakes with ease if you didn't downshift. Downshifting is really that bad for an auto? [Confused] How will it burn friction facings anymore than when the tranny downshifts automatically? Tall Paul, I ain't seen a shift kit for a Toyota Corolla yet!!! Manual valve body??? ****, maybe a turbo 400 could be wedged into this hotrod [LOL!]
I must say that my mom's Olds 88 gets driven a lot on the same moutain roads I described (parents have a cabin in the moutains), and it's been downshifted to **** and back. My mom goes for some SERIOUS rpms sometimes. Original tranny with 115K! My Dad's truck is another story; it's on it's 3rd tranny.
The being in gear isn't so bad. I'd be more worried about the return trip uphill with staying in gear under high engine load and max'd out cooling capacity. The coast end of things is the least of your worries, imho. The most wear in a trans is in the action of the shifting itself. This is where, to give us that smooth shift, there is an overlap of applications as they transition. All your shift kits make this sloppy and wearful action much more abrupt (so now you buy universals instead of trans rebuilds [I dont know] ) I visited a friend in western PA. I went out the turnpike ..which goes through the mountains. Since there was a perpetual construction site on the way out ..I went back via Rt. 30. I never spent more time in my jeep at WOT in 2nd gear going from one 100 yard stretch to another semi-switchback. When I hit the summit (several) and saw one of those "9% grade ahead - all trucks must stop and proceed in low gear" signs ..I pulled over to cool the trans off (just in case). Throw on a trans cooler ..swap to synth annual changes ..get one of those in-line trans filters ..and be happy.
I've been over Hoosier and many other Colorado passes and you definitely do not want to rely on brakes alone coming down. I don't know how old your tranny is but if it has a vacuum actuated shift modulator, you can make a tiny leak to firm up the shift (makes it think you foot is farther into it than it really is). Did it to wife's Aerostar and really love driving it now (hmmm, hope that is not what is causing my ping, Gary). [Big Grin]
Well, it's an 02, so I'm guessing it's all electronic. To tell ya the truth, it shifts really firm as is! I like it much more than many of the GMs I've driven that shift all slow. Seems like every little import 4 banger with an auto I've driven shifted firm; not like shift kit firm, but quick and crisp instead of slow and sloppy. And it downshifts really quickly when you punch it, which is all the time since it has no sack whatsoever.
What gets me are cars that go PRND31 and you can't even pick 2nd gear. Your corolla will be fine; being all electronic I bet it bumps up the line pressure for a firm downshift. Being in Manual 2nd is a different scene from being in Drive, and coincidentally in 2nd, which is sloppier.
Given you have firm (or should we say quick) shifts with the stock tranny, blupupher's advice is right on. I like my motorhome PRND21 (the D is in an O)because most of the manual shifting I need to do is in and out of overdrive and for that there is a pushbutton on the dashboard. It also has a Banks Transcommand module that makes it shift beautifully as the Ford E4OD is otherwise known for sloppy shifting.
I can't imagine not using the gears in an automatic. I also can't imagine why anyone would be scared of it. Moving along at a good speed will keep the package cooled (stock radiator cooler), and easing off of the gas prior to shifting is the one thing I look to do. I'd certainly allow it to cool off for a while at low speeds (NOT idling, no airflow across cooler) before shutdown. We took a 14,000# V8-440/727-trans motorhome through Colorado on more than one occasion, and ran some of the passes higher than Hoosier (the Furds and Chibs powered 'homes were waiting for tow trucks to get them over), and we used that 727 just as hard as the motor . . . and it was at WOT for twenty-thirty minutes at a time a dozen times in a week. As to when to downshift on the upgrade: Make downshift as vacuum begins to fall off NOT rpm! (You'll need a dash gauge, try AUTOMETER). As to the down side, descend in the same gear in which you finished the ascent. We never did get to install the exhaust brake (DECEL-O-MATIC, a company out of AZ) on that 440, but it would have been a nice thing. A gear splitter would also have been nice. Trans shifted as good as ever when the 'home was sold at over 80m miles.
I never downshift manually when climbing grades; I let my right foot do the downshifting then. And I'm very easy with it like you described TanSedan. Thanks for the tips gentlemen; keep um comin if ya got more to add. I don't think I'll add a tranny cooler but I'm thinkin hard about a synthetic ATF. What's the best? Redline? Or, since it has a drain plug for the trans, I was thinkin about just a drain and fill at most every year or sooner, and I'll drop the pan and replace the filter at say, 60K? That's what Toyota recomends. That'll be overkill with all the tranny drain and fills. Heck, ATF is cheap; I may do it like every other oil change!
I would run Redline ATF, especially if you are skipping the cooler. I think periodic partial refills (maybe every 20K and then a bigger refill every 60K when you drop the pan). B&M makes a pan drain kit that is easy to install provided you have a clear area inside the pan (I have on wife's Aerostar). And you are right, ATF is cheap, even Redline ATF, when compared to a tranny rebuild. With Redline, you probably are fine with a full change every 60K, but is it really a full change--few are.
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