I have a 06 Monte Carlo with a 3900 that has 215,000 miles on it and I seem to be losing 2nd gear. This car is in great shape for the year and miles but im not sure I want to spend the money on a brand new transmission. So I'm wondering what used transmissions I could replace mine with.

 

pick up any 4t65E tranny from any of the grand prix's, monte carlo's or impala's that are not supercharged and they will work. Sometimes you can buy a whole car cheaper than a used tranny, but going rate up here is around 600 from a wreckers with fairly low km's on it. Then all you need to do is install in the car and drive away

 

He has to stick with more modern transmissions, there is an electrical change starting in 2003 on some cars.

 

The ID tag on the used donor transmission has to match the one you're replacing. That tag is located on the passenger side near the transmission differential facing the rear of the car. Hard to see without taking off the passenger front wheel and crawling under the car.

Here's a link to an example of the ID tag: 4T65E ID Tag Info