Do you have a 4L60E harness, but want to upgrade to the 4L80E? 
 
Are you not interested in modifying existing wiring with the potential of miswiring, and are looking for something that you can plug up and go?
 
Look no further!  This is a popular item, and it's understandable. Once you actually hit the skinny pedal, most 4L60E transmissions end up behind your car.... pair that with all the boosts from your Wuhan Whistlebois and that poor transmission doesn't stand a chance.
 
Complete with instructions, this adaptive harness allows you to convert your existing engine harness with 4L60E transmission wiring to a 4L80E by simply plugging in the large adapter harness, and pinning two connections on your PCM connector. Thats IT!

You could be wired up for a 4L80E swap in under 30 minutes, EASY, and never have a worry about losing second, third, and fourth gear again.