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Old 04-03-2006, 12:36 AM   #1
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Default Downshift?

My '96 doesn't seem to like downshifting into first, I have to be going relatively slow for it to happen. It will drop down from 3rd to 2nd just fine, but even going 40 or 50km/h it won't drop to 1st @ WOT.

What is the maximum speed it should downshift to first at? Maybe I'm just used to the THM440 in the '89 which loved downshifting into first..

If this is odd, perhaps it is a TPS thing? Does it have to be replaced or just adjusted?

Thanks!
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Old 04-03-2006, 12:41 AM   #2
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it seems anything above 35 the car will hang in 2nd
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Old 04-03-2006, 12:46 AM   #3
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I'm talking kilometers per hour, 50km/h is like 30mph...
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Old 04-03-2006, 01:29 AM   #4
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The computer is goofy. If it sences you are gaining speed fast in second and you puch it at 25-30mph somtimes it won't downshift. But if you are just cruising at 35mph it should every time. Get it up to 40 and let it slow down to 35 then hit it real fast, gauranteed downshift. If it doesn't then yes the TPS is prolly messed up.
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Old 04-03-2006, 01:46 AM   #5
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well not nessicarily...the TPS is more engine related...its more for telling the engine how much fuel it is going to recieve...check out your TV cable...it is on the throttle body and you will see it leading down to the transmission...sort of move the throttle by hand and if you see the end of that cable head stop pulling before the throttle is back to idle, then it is out of adjustment...just check that...basically it is telling the trans when the pedal is being pressed and to what degree it is being pressed...then the TPS tells it how fast the vehicle is moving and therefore shifts...mostly the way it works is if you are going under 30 mph, the pedal should be pressed about halfway down and it will usually downshift, if going over 30 then the pedal will have to be pressed a bit farther, probably all the way down to get a double down.....you will probably get more of a pull in 1st gear, because it also controls when your pedal is not being pressed and can be shifted, but if it is in gear, as soon as you press the pedal, it should move the TV cable with even the slightest degree, if not, the trans still thinks that you are in a shifting mode and the TC will not respond as you wish it would.

Anyways, just check that and check back...
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Old 04-03-2006, 07:04 AM   #6
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Default Re: Downshift?

Quote:
Originally Posted by captainmiller
My '96 doesn't seem to like downshifting into first, I have to be going relatively slow for it to happen. It will drop down from 3rd to 2nd just fine, but even going 40 or 50km/h it won't drop to 1st @ WOT.
Cap, do you mean it will not kick down into first? I'm assuming if you coast down to a stop or a speed of a few kmph'* it will downshift into first gear.
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Old 04-03-2006, 08:15 AM   #7
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Cap...

1.Roll along at 50k'*... let off...to get it coasting. Nail that puppy to the floor board. Downshift? Yes.. good, no go tot step 2
2. Remove floor mat out from under pedal..try step 1 again. Downshift? yes..Good, No..uh oh
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Old 04-03-2006, 09:29 AM   #8
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W, the TPS is a primary factor considered for shifting. It senses how hard you're slamming the loud pedal. It'* also used for fueling, cruise control, and a couple other systems I can't think of off the top of my head (oh, T2V steering on the SSEi'* also).

92 and newer cars don't HAVE a TV cable. We have electronic transmissions, you have hydraulic.
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Old 04-03-2006, 03:54 PM   #9
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Had a Citation that did this once.
When it was cold and you slowed down it would hang in 2nd gear and not downshift into first. It was a sticking valve body. those cars used mechanical systems though.
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Old 04-03-2006, 05:43 PM   #10
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Captin thats a possibility...

The PCM is dependant on that TPS for fueling as well as load and kick down signal.. The PCM looks at the throttle angle and then will downshift when planted... At that low of a speed you should be able to hit first in a hurry..

In my 3.06 Ratio 95 SE I can nail first at 38-39 mph... But I don't feel like it his second.. Feels like it goes right to first...

I know what you mean about that 440-T4 tho...

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