Question about 1998 Chevrolet S-10 Pickup

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Auto tranny will not shift out of 1st gear.

I changed a vacuum line on the top of the manifold, left side from the front. the line ran around the TBI/ Carb to a Tee on the right side of the firewall. I replaced the rubber lines I could find there. This is a 4.3 L, Z engine code, 2wd. I replaced the speed sensor, no change. Also the speedo is inoperable. Where are the " other " vvacuum lines routed/ located? I assume 1 must go to the trans. Where? Thanks.

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There should be a vacuum fitting on the rear of your engine that connects to a steel line. That steel line goes down under the fire wall to the rear of the transmission to a modulator valve. If you can't find it under the hood, crawl under the truck and start tracing from there and plug it in. That should solve your problem with shifting You probably have an electric speedo and I'm lost on that.

Posted on Jun 18, 2009


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Sounds like the modulator or a vacuum line..
The modulator tells the trani when to shift and is controled by vacuum presure..
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Or maybe the modulator linkage is stuck..
Changing the fluid is a good idea too..

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