In this video, Robert Bateman teaches me the importance of their center support stabilizer. He explains it to me while I perform the installation using their special kit.

This kit is available from major transmission parts suppliers like wittrans.com and transtar1.com, as well as many others.

The kit part number is K45990BI. Go to a trans parts supplier and enter the part number. For some reason, google doesn't find it very well.

The kit provides enough parts to fix 5 transmissions, but if you order the 6L80 MAX kit, it will come with the stabilizers so your jig will continue working until you wear out your drill bit or reamer, which you can by separately.