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Tim's Auto Repair
Tim's Auto Repair, mechanic
Category: Chevy
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Experience:  Have owned a repair shop for 25 yrs.
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1999 Chevy: 4wd..problems with voltage upsurge..hard shifting

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1999 Chevy 4wd 350 3 door truck...having problems with voltage upsurge upon startup...rough idle..then hard shifting from 1st to 2nd and 2nd to 3rd....very annoying


the first thing to do here,,is a load test on the chrging system,,,the load test will determine if you need a alternator...the voltage regulator on these is built into the alternator......if you dont have a load tester,,auto zone and most parts stores will do a load test for free...sense you get no codes,,this is where to start with your problem,,,i would think you may need an alternator


Customer: replied 4 years ago.

Is this a common problem..and lead to the shifting problem? It is very weird...I was going 65 on interstate..and it showed 19v...then started missing..I had to pullover...and wait a few min...then ran fine..but shifted I said. Are you sure that an alternator can cause such shifting problems? does sound as if it is the is not real common but does happen...yes,,the high voltage may make the transmission to act weird,sense the transmission is computer the load test


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Customer: replied 4 years ago.

Well today I am going to replace alternator. I tried to drive it..and it started and immediately went to over 19 volts and drove about 10 feet before stalling...this happened until I backed it back up to park in driveway. I did look up the RPO codes and have removed the old alternator and it is a 100 amp. I am going to replace it with one from Advance Auto today....


I will let you know whether the problem is solved with new alternator

yes,,please do



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