transmission is shifting late and hard.

2000 JEEP GRAND CHEROKEE
175,000 MILES • 6 CYL • 2WD • AUTOMATIC
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JOSH88
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whenever i hit the gas the rpm's go up normally but when it gets to the point of shifting into second gear it will keep on reving up until it finally shifts. It's very noticable and it just shifts very rough. It does it with all the gears; its worse when ever i give it alot of gas. The transmission could be going out,but who knows it could be something simple. Thank you.
Aug 6, 2011 at 6:48 AM
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CARADIODOC
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Older transmissions had a cable that would stick sometimes. I checked rockauto.com and they show a "modulator" for your vehicle. I don't know where it lives but given the o-ring in the photo and the fact it measures engine vacuum, I suspect you'll find it somewhere on the intake manifold.

There could be a problem with this unit but first check for a vacuum leak. That would cause the same low vacuum as when you're accelerating. The Transmission Computer will interpret low vacuum as heavy acceleration and increase the shift speeds and harshness.
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Aug 6, 2011 at 7:57 AM