I am on the same boat as u are. I started my swap of a 5.3 into my '94 W/T 6 weeks ago and plan on keeping my 4L60. From what I have read too, u can swap out the trans internal harnes to that of a later one, like a 1998 and it can be controlled by the LS pcm. The bad thing about '94 and older 4l60, is that they have PWM. Its suppose to soften the shifts. Mine does not have it. I also read on one of the treads, that u can simply have the PWM removed from the PCM when u flash it. That's what I plan on doing when I send it out to the guy at lt1swap.com in a few weeks.