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As we work to develop support for ten speed transmissions, we swapped the 4R70W in our 2004 Mercury Grand Marquis for a 10R80 transmission. If you'd like to learn more about the swap, such as the modifications and challenges we encountered, check out our video series which documents the Silver Bullet Project and gives advice that can be relevant to any transmission swap. Much of the information in this series also applies to the 6R80 because of how similar it is to the 10R80.

We'll be posting more information on the swap soon, so check back from time to time as we update this page.


We had to modify the crossmember to allow a 10R80 (or 6R80) to be mounted in the panther body. Here is a diagram showing what we did to it. You can also watch the crossmember video, available from the playlist above.

Crossmember Mod