overdrive problem

2000 PONTIAC GRAND PRIX
140,000 MILES • 3.8L • V6 • FWD • AUTOMATIC
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GPGTJIM
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car shifts fine first to second, second to third always. When shifting from third to overdrive it often slips, the tachometer shows the rpm indicator is waving around. If I punch the gas peddle it sometimes makes it shift. Going uphill it downshifts okay, but then wont return into overdrive till about 5000 rpm's. I recently had the transmission fluid and filter changed as the fluid was clear, now it is pink again and transmission behaves slightly better. They found almost no metal filings in the pan. Also tried some GM transmission additive little improvement. Is this indicating the over drive shaft splines are worn or is it worth trying to change out the pressure and shift solenoids?
Sep 2, 2016 at 12:03 PM
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SATURNTECH9
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Why was the fluid clear? When transmission fluid gets more miles on it it will eventually turn black. I have never seen the fluid turn clear. Was it milky?
Sep 2, 2016 at 1:19 PM
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GPGTJIM
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no it almost looked like new motor oil. The service centre had no explanation except they had to flush the system twice to get it done right and they wondered that it still shifted at all.
Sep 2, 2016 at 9:53 PM
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GPGTJIM
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oh, I forgot to say that the transmission has always made a whining noise in lower gears. I have put about 9000 miles on it since I purchased it last summer.
Sep 2, 2016 at 9:57 PM
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STRAILER
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It sound like the transmission is worn out and needs rebuilding. The whine comes from the trans filter being plugged with clutch material.

Please let us know what happens so it will help others.

Best, Ken
Sep 5, 2016 at 9:55 AM
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GPGTJIM
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Ken, I have recently had the transmission flushed and the filter changed this did not make any difference to the whine.
Sep 6, 2016 at 9:19 PM
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STRAILER
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The only other thing I have seen that would make the transmission whine is the front pump is going out which means a rebuild is in order.
Sep 14, 2016 at 4:59 PM