73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: betterton_ss on July 29, 2011, 12:19:25 pm

Title: premature shifting
Post by: betterton_ss on July 29, 2011, 12:19:25 pm

Hey guys sorry if this one has been on here, used the search button but found shifting hard and late shifting.  Ok i have a 76 1/2 2wd gmc.  Has 350/th350, don't know what gears it has in it but at 60mph it runs around 2200 to 2300 rpm.  I have 275/60/15 tires on it.  My problem is i think it is shifting to early. between 1/4 and 1/2 throttle it will shif around 18 mph and between 1500 and 2000 rpm.  The carb has a dead spot which i haven't rebuilt it yet.  could it be the carb or modulator?

Title: Re: premature shifting
Post by: bobcooter on July 29, 2011, 02:25:49 pm

You can screw in on the screw inside the modulator a couple of rounds and see of that helps. Be careful not to go more than 4 rounds. Just pull the vac hose and the screw is inside the vac line connection. It's very small. You'll need a little pocket screwdriver. Just an idea.

Title: Re: premature shifting
Post by: betterton_ss on July 30, 2011, 12:20:54 pm

thanks i didn't even know you could do that

Title: Re: premature shifting
Post by: bobcooter on July 30, 2011, 10:08:38 pm

I always try the cheap, easy things first. ;D