why wont my3L80 shift when cold

1990 CHEVROLET SILVERADO
95,000 MILES
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JEFF REED
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  • 1 POST
1990 chevy k2500 when cold will shift only at very high revs. once its warm it shifts just fine. i installed 2 new vacuum modgulators with no difference in shifting issues. it acts like when cold im not getting any vacuum to modgulator to get it to shift.
Nov 9, 2011 at 7:19 PM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
you need to look at the governor as well. it has a plastic gear that tends to dish and effects the shift points. i would also add some valve body modifier for the valves especially if one is sticking.

Roy
Nov 9, 2011 at 7:24 PM
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