Engine 2000 VS 2003 Balance


Jul 19, 2006
Boise Idaho
I replaced the motor from my 2003 3.8 V6 Automatic with a motor from a 2000 3.8 V6 Manual. I removed the pilot bearing and and transferred over the flex plate. The replacement motor (2000) has tons of vibration. I am about to replace the harmonic balancer but have read that they are different between 2000 and 2003 due to the newer motor being internally balanced.

Can someone please enlighten me.

Do I need to replace the flex plate or not? If one is externally balanced and the other is internally wouldn't the flex plate be an issue.

The 2000 motor has the Harmonic balancer that came with it. It does not look bad the rubber is in excellent shape.

Or do the actually use the same balance and I have a bad balancer that just looks good.
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Mod Dude
Mar 7, 2002
You need to replace it. The 2000 engine had a different flexplate... sort of. In 2000, there were two different flexplates, one was the same as your 2003, the other is an inch bigger. RockAuto doesn't state whether they're balanced differently or not, but when you look at flywheels, it does, which would seem to be your smoking gun.

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