1. Autos
Send to a Friend via Email

Your suggestion is on its way!

An email with a link to:

http://autorepair.about.com/library/faqs/bl187e.htm

was emailed to:

Thanks for sharing About.com with others!

Questions and Answers

Chevy Monte Carlo Shifts Funny

Q. Mr.Ciulla, I just had to take my 2000 Chevy Monte Carlo SS to the dealer because the engine misfired and the check engine light came on. It ran fine after the initial misfire but the car did not shift properly, especially in the bitter cold weather. After warming up the transmission finally shifted into 4th gear.

Chevy Monte Carlo Shifts Funny

The dealer got a code of "P0420" from the computer and said the code was intermittent after a 15 mile test drive. I took the car home and the next morning the transmission still wouldn't shift properly. The temperature was around 20° here in Baltimore that morning. I don't here the transmission slipping but the engine is running anywhere from 500 to 1,500 RPMs more than normal at a certain speed while trying to shift.

By the way, the dealer said when the engine light comes on the transmission will not shift properly, which I find hard to believe. I asked another mechanic if maybe I should service the transmission but he says no. The car has 38,000 miles on it. If you would be so kind as to give me your take on this it would be greatly appreciated. Just for your info the car is stock with no modifications.

Thank you,
Greg

A. Some DTC's will cause the transmission to "default" to a different shift pattern in order to help prevent the transmission from self destructing. A P0420 sounds like a catalytic convertor code. Low efficiency in the catalytic convertor should have nothing to do with the transmission but it could affect the shifting. There may be new software out for this or the misfire was bad enough to hurt the catalytic convertor that would still be under warranty.

Additional Information provided courtesy of ALLDATA

Back to Index

©2014 About.com. All rights reserved.