1997 GMC Suburban won't downshift/sluggish

1997 GMC SUBURBAN
144,500 MILES • V8 • 4WD • AUTOMATIC
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SWIMMER1967
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I have a 97 GMC suburban that had a complete transmission rebuild about a year and a half ago. Since then, I have put about 10000 miles on it. Today, I noticed that from a dead start, it feels like it starts in second gear (very sluggish). I put some transmission fluid in and that didn't help. In addition, it seems that it won't shift into 4th on the highway. I can maintain speed, but judging by the rpm's, it looks like it doesn't shift from third. Finally, when I "stomp" on the gas, it doesn't downshift, only dumps gas in the same gear and is real sluggish on acceleration. Anybody have any ideas?
Jun 11, 2009 at 2:02 PM
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DOCFIXIT
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Hi
1-2 shift valve maybe faulty needs to be on for first gear andOD. The kick down at WOT is another problem more likely a hydraulic issue.
Will trans go into First manually? Was there a warranty on work?
Let me know
Thanks for donate
Jun 12, 2009 at 2:42 PM
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SWIMMER1967
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I can shift through low 1-2-3 without any problem, it seems. Another interesting note, I let it sit overnight and drove it this p.m. to the bank. Worked just fine! (no sluggish, downshifted fine, etc.) Came out of the bank and the problem was back. Could be something with O2 sensors???? Don't get that one. As for a warranty, I think it was only a year, but the guy was pretty good and might be able to work with me.
Jun 12, 2009 at 4:50 PM
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DOCFIXIT
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It maybe an input or out put speed sensor see if the trans shop will scan trans and see if can find problem.
Jun 13, 2009 at 10:26 AM
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COUEY2
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Hi,
I am having same prblem and my tranny is less than a year old. My transmision guy coded it out and told me it had to do with the ignition. I replace dthat and now it is still doing it and still giving the ignition code. Any ideas?
Sep 14, 2009 at 10:49 PM
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DOCFIXIT
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What is code your getting in P0xxx format
Sep 15, 2009 at 1:53 PM