# S-10 blazer

**URL:** <https://community.cartalk.com/t/s-10-blazer/41748>\
**Category:** Maintenance/Repairs\
**Tags:** chevrolet, blazer\
**Created:** [January 3, 2010, 3:03am UTC](https://community.cartalk.com/t/s-10-blazer/41748 "2010-01-03T03:03:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![lilspeed08](https://avatars.discourse-cdn.com/v4/letter/l/51bf81/32.png) [@lilspeed08](https://community.cartalk.com/u/lilspeed08)\
**Post date:** [January 3, 2010, 3:03am UTC](https://community.cartalk.com/t/s-10-blazer/41748/1 "2010-01-03T03:03:36Z")

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i have a 94 s-10 blazer with a 4.3 vortec in it… its having problems shifting into 3rd gear and overdrive… what might be the cause of this problem?

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**Author:** ![Manolito](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/manolito/32/3070_2.png) [@Manolito](https://community.cartalk.com/u/Manolito)\
**Post date:** [January 3, 2010, 4:10am UTC](https://community.cartalk.com/t/s-10-blazer/41748/2 "2010-01-03T04:10:16Z")

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I am a complete rookie with automatic transmissions, but I would start by looking at whatever it uses to downshift - a vacuum actuator? a cable?

Your best hope is that whatever actuates a downshift is trying to downshift all the time. If it is vacuum, look for a failed hose or a leaking diaphragm actuator at the transmission.

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**Author:** ![transman618](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/transman618/32/24_2.png) [@transman618](https://community.cartalk.com/u/transman618)\
**Post date:** [January 3, 2010, 5:06am UTC](https://community.cartalk.com/t/s-10-blazer/41748/3 "2010-01-03T05:06:47Z")

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This transmission is fully electronic meaning no TV cable and no vacuum modulator. Unfortunately the 3-4 clutches in this transmission are a weak link and commonly fail. I would have a trans shop check it out and confirm 3-4 failure.

transman