Engine or Trans. ?
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Engine or Trans. ?
I have a 2001 f150 5.4l 4x4 4r70w trans. with 71000 miles. When the engine is cold and I change from park to reverse ther idle climbs up approx. 300-400 rpm and then drops into gear. It is lower when the engine is warm or when shifting from reverse to park. Trans fluid looked fine changed anyway. Pulls strong through all gears and does not slip. Is this a problem? Seems like the rpm should not climb that much to me between gears. I am afraid it is going to break a u-joint. I just bought the truck. So I cannot say how long it has been this way. The engine starts at approx. 1100 rpm, and decreases the idle normally as the engine warms up. Idles when warm around 700 or so. So I don't think it is the IAC.
Thanks
Frank
Thanks
Frank
Lead Driver
Joined: Sep 2006
Posts: 7,907
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What your discribing is normal.
Cold starts opens the IAC for high idle or the motor would stall.
The rest of your discription is normal for the idle to come down to about 700 as it should as the motor heats..
Nothing wrong with the IAC if it is controlling the idle that well.
All present day systems do the same thing.
Going into gear from a high idle should not be as harsh as your indicating because the converter fluid slip should soften it.
If something is banging then a slop is present in the drive line at some point..
Good luck.
Cold starts opens the IAC for high idle or the motor would stall.
The rest of your discription is normal for the idle to come down to about 700 as it should as the motor heats..
Nothing wrong with the IAC if it is controlling the idle that well.
All present day systems do the same thing.
Going into gear from a high idle should not be as harsh as your indicating because the converter fluid slip should soften it.
If something is banging then a slop is present in the drive line at some point..
Good luck.
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ExplorerTom
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Dec 13, 2004 11:00 AM
