2003 Buick Rendezvous transmission

2003 BUICK RENDEZVOUS
178,000 MILES • 6 CYL • AWD • AUTOMATIC
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MPLAIN
  • MEMBER
  • 24 POSTS
Between 3rd and 4th gear it don't want to shift but does if you let up on the gas.
Feb 15, 2015 at 1:06 PM
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HMAC300
  • CAR REPAIR CONTRIBUTOR
  • 48,601 POSTS
check fluid level and scan for codes it may be a valve body problem or clutch problem.
Feb 15, 2015 at 3:29 PM
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STRAILER
  • CAR REPAIR CONTRIBUTOR
  • 54,334 POSTS
To me it sounds like the catalytic converter might be bad and starting to clog up, when this happens the engine vacuum is lower and it makes the computer think you are going up a hill. Here is a guide to help test the cat and the cat location in the images below.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Also, let's check for codes

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Check out the images (below). Please let us know what happens.
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Jun 27, 2024 at 6:31 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.