99 Lumina shifting problems

1999 CHEVROLET LUMINA
276,000 MILES
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GEOZOR
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  • 1 POST
I just rebuild my 3.1 M engine.Before the rebuild I had transmission problems, and I had replaced the vacuum modulator with a cheap adjustable one.With the rebuild I found that the TPS was broken.Anyway everything works and I have tryied to adjust the modulator many times but the car still will not shift before 4000 rpm.Any ideas on how to adjust the modulator before I throw it in the garbage?
Dec 19, 2011 at 9:43 PM
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HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
it's probably not the modulator. It could be a govenor or bad electrical connection. take to a trans guy and have him scan it for codes. It could be a stuck valve in trans.
Dec 19, 2011 at 11:25 PM
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CADIEMAN
  • ✓ASE Certified Mechanic
  • 3,544 POSTS
  • ASE Certified Mechanic
get a new modulater.those cheap ones are only good for a few adjustments than thier junk.
Dec 20, 2011 at 12:11 AM
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