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Enthusiast Joined Apr 12, '07 From Ferndale, MI Currently Offline Reputation: 0 (0%) ![]() |
couldn't find much on automatic transmissions, but i thought i'd give it a go.
I have a 97 Celica ST with an automatic transmission ~150,000 miles on it. When the temp drops below 60 F it hesitates to shift to fourth gear and will rev up over 4000 rpms before it shifts. This only happens before the car warms up, all subsequent shifts are fine. I now warm up the car for a few minutes before driving it, and it solves the problem. Should I change the transmission fluid? To my knowledge it's never been changed, but I've heard differing opinions on this. Some say to change it and some say it will do more harm then good since it's old/high miles. What should I do? I don't know much about cars...just a girl ![]() thanks |
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![]() Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Sep 6, '04 From oakdale Mn Currently Offline Reputation: 0 (0%) ![]() |
could be the valve body. i'd call a tranny place and get an estimate and have them diagnose it rather than spending money on parts that you don't need. most likely it's the valve body.
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![]() Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Oct 10, '03 From Wichita, KS Currently Offline Reputation: 5 (100%) ![]() |
That's just how it's designed. Early shifts and no shift to overdrive until warm.
-------------------- ![]() Project ST204.5 99.88946% complete... |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Mar 11, '06 From Way South Chicago Currently Offline Reputation: 0 (0%) ![]() |
QUOTE(WannabeGT4 @ Sep 21, 2007 - 2:43 PM) [snapback]597940[/snapback] That's just how it's designed. Early shifts and no shift to overdrive until warm. and also no OD till the engine is warmed. this serves two purposes, one to protect the engine from being revved high till its warm and secondly to protect the trans from hard WOT shifts till its fluid is warm as well. -------------------- |
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Enthusiast Joined Apr 12, '07 From Ferndale, MI Currently Offline Reputation: 0 (0%) ![]() |
Thanks guys.
You're totally right. I looked through my owner's manual and there it was... Guess I only noticed because my commute changed and my car doesn't get a chance to warm up before I'm on the freeway. |
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![]() Enthusiast ![]() Joined Feb 8, '07 From Oakland, Ca USA Currently Offline Reputation: 0 (0%) ![]() |
This is pretty much the same principal that those cheap "chips" work on. They try to trick your engine into thinkiong that the air is a lot colder than it really is which should increase response time and increase the shift points. All they really do is make you waste gas.... but yea... my AT does the same thing...
-M -------------------- -M-
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![]() Enthusiast ![]() ![]() Joined Apr 16, '06 From Jackson, MS Currently Offline Reputation: 0 (0%) ![]() |
My cars the same way, once it gets passed like a quarter inch above cold it shifts and o/d kicks in. Nothin wrong with it.
![]() Edit, no clue why I posted this, didn't bother to read that you had found it in the manual. lol ~FlamingCelica This post has been edited by FlamingCelica: Sep 26, 2007 - 6:15 PM -------------------- 94 Red Celica ST
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Enthusiast ![]() ![]() ![]() Joined May 19, '06 From North NJ Currently Offline Reputation: 16 (100%) ![]() |
shoes
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![]() Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Oct 10, '03 From Wichita, KS Currently Offline Reputation: 5 (100%) ![]() |
QUOTE(Manny @ Sep 26, 2007 - 4:07 PM) [snapback]599335[/snapback] This is pretty much the same principal that those cheap "chips" work on. They try to trick your engine into thinkiong that the air is a lot colder than it really is which should increase response time and increase the shift points. All they really do is make you waste gas.... but yea... my AT does the same thing... -M Totally different actually. The "chips" are resistors inline or in place of the IAT(intake air temp) sensor. The Shift points are determined by the coolant temp. -------------------- ![]() Project ST204.5 99.88946% complete... |
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