Transmission problem

1999 PONTIAC GRAND PRIX
225,000 MILES • 3.8L • 6 CYL • FWD • AUTOMATIC
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PAUL ED
  • MEMBER
  • 1 POST
Lost cruise control about a month ago. Then car would not shift out of first. I could manually shift into second at thirty five mph. But would not go into 3/4. I had no drive or overdrive. I changed transmission with a rebuilt one. Still have the same problem. Will not shift.
Sep 14, 2017 at 8:42 AM
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STEVE W.
  • ✓Experienced Mechanic
  • 15,390 POSTS
Did you re-use your old range sensor? Other sensors? As the problem is still there with a different transmission I would suspect either bad wiring or a bad sensor. If you have access to a dealer level scan tool you could go in and manually test the transmission while watching the tool and seeing what stops working.

Start by testing all the related fuses, TCC fuse in the junction block, ECM Sense fuse, cigarette lighter fuse. Use a test light to verify they are good.

Sep 14, 2017 at 3:13 PM
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