4L60E - 2009 (and later) incompatibility issues

Discussion in 'High Tech Retrofits' started by mrvedit, Jan 9, 2011.

  1. mrvedit

    mrvedit Veteran Member

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    Jun 12, 2009
    Ann Arbor, MI
    For those people looking to swap a 4L60E/4L65E transmission into their car, I wanted to give an early warning that 2009 and later transmissions are electrically incompatible with 1995-2008 units. Therefore any pre-2009 PCM/TCU will not work with them. The same will be true for any aftermarket controller not explicitly designed for the 2009 change.

    First, the 3-2 shift solenoid was eliminated. More importantly, the "Pressure switch assembly" was replaced with a shift-linkage switch assembly. While the electrical connector appearance didn't change, it now has several new pins in it.

    I encountered this issue when I swapped a 2007 LS2 engine with a brand new 4L65E into my '81 Camaro. The PCM reported an error that the the 3-2 shift solenoid was defective and when I went to replace it, I discovered it didn't exist.

    My solution was to purchase a "broken" 4L60E trans (easily found for $100 with "blown reverse"). I removed the valve body, bought a new wiring harness and solenoids, and installed it with no problems on my 2010 4L65E. The computer is happy and the transmission shifts exactly as programmed, including lockup.

    With the transmission valve body removed, it was also a good time to install a shift kit. I chose the Transgo product. (But left out the mod that allows a forced 2-1 shift at any speed.)

    I'm sure more experienced advice will be forthcoming on this topic; I just wanted to give an early warning.

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