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SC400 Tranny Problem

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Old 08-12-03, 04:11 AM
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SCmist
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Default SC400 Tranny Problem

I need some help trying to identify a problem with my tranny. The first time of the day when I start and the drive my car; when I accelerate a little quick, from 1st gear it doesn't want to change to 2nd gear (driving in "D"). As I accelerate more, the rpm just climbs and the tranny doesn't want to shift. So all I can do is just back off on the gas a litte and then it switches gears. The funny thing is that it only happens to me the first time of the day when driven. And after that, I can mash on the pedal from dead stop and it switches gears fine.

It's been going on for about two months now. I changed the tranny fluid with T-IV about two weeks ago and thinking it might do the trick but it didn't. I also remember reading a couple posts about some of the members having problems with the torque converter. So right now I have myself confuse that it might be the torque converter. I tried searching back but couldn't find the post. So most diffintely I know its the tranny but just not sure what part that is the problem. Hopefully you guys can help me out. Thanks.
Old 08-12-03, 11:36 AM
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matt7184
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Try reseting your ECU, that may help.

I noticed that you said when you accelerate quick. We'll the computer may be thinking you want to hold the gear longer, so see if your PWRECT is off and make sure overdrive is off too.

Last edited by matt7184; 08-12-03 at 11:37 AM.
Old 08-12-03, 08:25 PM
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THE_CEO
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ditto!....excellent advice....our trans are just about bulletproof!

CEO
Old 08-12-03, 08:47 PM
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SCmist
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thanks guys. i try it and let you know if anything changes.
Old 08-18-03, 10:34 PM
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Hi everyone, I tried what matt7184 suggested but nothing has change. Does anyone else have any ideas?
thanks
Old 08-19-03, 05:02 AM
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VSsc400
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do a full transmission fluid change. (the whole 14qt's of it) also make sure the pan gasket seal is still intact.

for a while i was running without one of the primary o2 sensors(had a wideband attached but that's another story) and it was holding 1st gear without much power. I would do the tranny flush then check the o2 sensors.
Old 08-19-03, 05:38 AM
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Keith13b
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Sounds like the tranny ecu is keeping rpm's up to warm the engine to optimum temp. Once there, everything is normal- Is that what you are experiencing?
Old 08-19-03, 06:43 AM
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SCmist
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VSsc400- How do I perform a full tranny flush? Because I have a body shop available to me, so I don't wanna spend more money at the dealers. Got to spend the money into other mods
Also, What should I do to check the main O2 sensors?

Keith- You brought up a very good point, every morning or first time of day that I drive the sc, same routine. It doesn't want to shift from first to second. It would be like this for one or two times starting from first gear. so when it happens, I just back off a little in accelerating then it finally shifts.

Before, I was thinking the problem was with the tranny itself. Now, not so sure. Its been going on for a couple months now. I still continue to drive about 6 days a week, same routine. No other problems.

Last edited by SCmist; 08-19-03 at 06:44 AM.
Old 08-19-03, 11:01 AM
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The OEM tranny ecu will keep rpm's up until the car is at normal operating temp. This is normal BTW. Backing off the gas and forcing a shift won't hurt anything, but my logic is.....let the car do its own thing, as many hours of R&D went into making such a fine automobile. In other words, it does it for a reason.
Old 08-19-03, 06:53 PM
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How high are you revving the engine when its cold? I never rev my engine above 3k until its fully warmed up except once and the computer limits how high it will rev. If its shifting fine and its only your shift points it is more likely your tranny ECU than your actual fluid needing a flush (btw, if you do a flush make sure you use toyota fluid, people have problems with other fluids).
Old 08-19-03, 08:43 PM
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SCmist
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Keith - If thats the case, then we have one F***ing smart-*** car.

Matt- I don't rev the car, I let it warn up on its own. But sometimes when I'm in a hurry, I just start it and go, but I drive it a slower than normal for the first couple minutes.
Old 08-19-03, 09:06 PM
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Take a look at the transmission oil from the dipstick. Place some on some white paper. Does it have any particles or look charred? Does it smell burnt? If so then head to a shop.
Old 08-20-03, 05:18 AM
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Originally posted by SCmist
Keith - If thats the case, then we have one F***ing smart-*** car.

Matt- I don't rev the car, I let it warn up on its own. But sometimes when I'm in a hurry, I just start it and go, but I drive it a slower than normal for the first couple minutes.
Yes, but the car can be too smart for its own good sometimes, especially if youre trying to mod it! Thats why anything short of a stand alone will be cancelled out by the factory ECU over time. SO just be careful dropping money into computer upgrades.

The ECU should hold the rpm's around 2K untill warmed up, or forced to shift.
Old 08-20-03, 08:01 PM
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Make sure your ignition is in good shape;that can effect the vacume signal,which is used to determine when to shift.Also check for vacume leaks too .
If you're confident that the car is in good tune in that way,you can tweak the mixture screw slightly to gain proper mixture after changing the intake.That is in the airflow meter,under a sealed plug,and not meant to be messed with,so only very small adjustments will do any good before falling out of range.Always mark exactly where the thing was to begin with.
But it's most likely an ignition thing,or vacume leak.
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