This may have already been answered, but I couldn't seem to find it. A friend of mine has a 97 Formula with a blown up 4l60. I've heard you have to use a later model 4l60 due to computer complications, but i was wondering would he be able to use a 4l60 out of a 2wd s10 or blazer, or even a 2wd 1500 or tahoe or something like that? Basically what im asking is 2wd 4l60 used in trucks and suvs useable in an lt1 fbody? I realize that LS based motor's 4l60 will not fit. But perhaps from late 90's-early 2000's 4.3 trucks or 5.7 vortec truck? Thanks for any help and sorry if im beating a dead horse with this question.

 

Don't take this as gospel, but I'm pretty sure 1of this....
He needs a '96 or '97 trans OR a '98+ from a V6 engine, which will have a 298mm input shaft and NO bolt hole at the 12 O'clock position. You are correct that a trans from an LS engine will not work.
Avoid any '93/'94 and '95 as these are very year-specific and electrically incompatible with any other year.
IMHO '93/'94 was an Alpha-test, '95 was a Beta-test and it wasn't until '96 that GM finally figured out how to electronically control the trans. No further electrical changes were made until '05/'06 when ISS (Input Speed Sensor) was added and even that is not incompatible. Around '08 significant changes were again made which are incompatible with earlier years.