Different year motor swap

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Mar 30, 2025 | 6:31 PM

Spudwrench 12

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Joined: Nov 2019

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Different year motor swap

I have an 04 with a 5.3 and want to swap it with a 99 low mileage 5.3 . eBay says they are not compatible. If I use my 04 electronics on the Motor why wouldn’t it work ?

Apr 3, 2025 | 2:26 PM

jfmorris

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Joined: Mar 2024

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From: Huntsville, AL

There were 4 different engine codes for the 5.3L, which was made from 1999 to 2014. LM7, L59, LM4, and the L33. Maybe the 1999 is a different one than the 2004, and incompatible with your vehicle electronics?