Transmission not shifting properly

KBVIDAK

MEMBER
2008 CHEVROLET IMPALA
3.5L
V6
2WD
AUTOMATIC
160,000 MILES

My car has overdrive but stalls very badly while in first, if I manually shift it, first gear works. Sometimes it works fine, the other half of the time it doesn't. Please help me.

Tuesday, January 25th, 2022 AT 8:54 PM

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

I just want to clarify the issues. Do you start the engine, and it stalls or does it only stall after you drive the vehicle?

So, the way I understand this is if you drive the vehicle then it goes into overdrive and then when you slow down to 1st gear, the engine stalls?

If this is the case, then we need to suspect we have an issue with the torque converter.

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

This means we need to check the fluid and see what it looks like. If it looks dark, then we need to suspect the converter is locked and this is creating heat in the transmission causing the fluid to burn.

What is happening is the converter locks and doesn't release and then it stalls when the speed is low enough. Basically, it is just like not pressing the clutch in on a manual transmission and the engine stalls.

I am attaching the info from the manual on diagnosing the converter, however, let's make sure this is what is happening and then we can go from there.

Thanks

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