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12-13-2023, 03:45 PM
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#1 |
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Registered User
Join Date: Nov 2017
Location: H, Q
Posts: 180
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Shifting at high RPM
Greetings
My 1986 GMC Sierra K2500, 5.7L, with auto transmission, developed 2 issues.🥱🥱🥱🥱🥱 1. It will not shift from 1st to 2ed as normal, it shifts at high RPM/higher speed. I check the vacuum hose from the manifold port (behind the carb) to the vacuum modulator valve, suction is good. Not sure about the modulator valve if working or not, no one around knows how to diagnose the issue. Parts have to be ordered from US it takes 15-25 days.🤒 Tran has no click down cable to the carb, it has an electric wire (left side of Tran-driver side) to a switch attached near/at the accelerator peddle. Not sure how to fix this high speed shifting.🤔 2. The choke light is on all the time, oil pressure is very good. Not sure why. 🧐🫡  If someone can help 
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1972 GMC Sierra C2500, V8-350 1986 GMC Sierra C2500, V8-454 1986 GMC Sierra C2500, V8-LS1 1986 GMC Sierra K2500, V8-350 1987 GMC Sierra R3500, V8-454 1997 GMC Sierra K2500, V8-454 Last edited by LockDoc; 12-16-2023 at 12:56 AM. |
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