Pretty old thread here but might as well post my findings since it got bumped up. I recently had to have the 4L60E in my V6 truck rebuilt and I had a TransGo HD2 shift kit installed along with Superior billet servos and a beast sunshell. I already have a tune from Black Bear Performance so that helps too I'm sure, but man this is a hard shifting combo. I'm very happy with it, though. Exactly what I was looking for. Have to be careful on rainy days or in any kind of slick conditions now, any kind of moisture on the road and it will roast the tires into second in a fairly violent manner at WOT. 3-4 shift isn't nearly that bad but will still definitely get your attention. If you're looking for hard shifts this is the way to go. My builder told me he wouldn't recommend using these parts without a heavy duty band as well, said the billet servos can be too much for the factory one.
