won't shift into overdrive

BUICK LESABRE
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SCOTT E. PETERSEN
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2001 buick lesabre custom, 105,000 miles, 3800 v6 engine. Transmission would not shift into overdrive yesterday, we started out with a cold engine and even after it warmed up it would not shift from 3rd to overdrive. stopped and ate breakfast ( 10 mile drive). Came out and drove home now had what sounded like a low fire whistle sound that would get higher pitched as engine rpm increased and still would not go into overdrive, got back home and had a hot smell coming from under hood(almost like a hot electrical component smell) checked tranny fluid and is normal as well as radiator fluid. Car ran fine day before. No idiot lights came on. also transmission was rebuilt exactly 1 year ago and new radiator with tranny cooler installed at same time. We have had alot of problems with this car........please help me out? Thanks
Nov 19, 2007 at 11:00 AM
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2CARPRO JACK
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Need to scan the powertrain for any transmission codes, most likely stored something if it wont shift into OD.

This guide can help us and I can tell you I have found that if the thermostat is stuck open it can cause this issue.

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

Also, with that kind of noise the catalytic converter can be partially clogged lowering the engine vacuum which will cause the transmission to stay out of overdrive.

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

Please go over these guides and get back to us.
Nov 20, 2007 at 11:21 AM