None of the '93 -'97 4L60E's are directly interchangeable, except '93 and '94 and '96 and '97
98-04 S10 and Astro are interchangeable. No 4l60e from a 99 up fullsize will work in an S-series regardless of what engine it had, including the 4.3. Different torque converter, input shafts and bellhousing.
Here's a list of yearly differences:
1993: These were used in TRUCKS only. Not available in F-Bodies, B-Bodies, or Vettes
1994: Interchangeable with '93 4L60E with no modifications. The '93-'94 is a NON PWM transmission. This means that the lock up apply strategy is an on /off arrangement. It has an 11 pin case connector. Does not have PWM cast into front pump. 1 piece TCC control valve in the valve body. Plate has holes in plate, marked in diagram below. 1st design 3-2 valve
1995: Stand alone year! Will not interchange with any other year. This is a PWM transmission. An extra solenoid was added to the valve body to control the pulsed lock up strategy of the conerter clutch. It has a 12 pin case connector, extra wire in the transmission to computer harness and different computer to control the new PWM circuit. Has PWM cast in front pump. Front pump internal passages different to match new TCC strategy. 2 piece TCC control valve in valve body. 1st design 3-2 valve. 12 pin case connector. '94 computer won't recognize new TCC strategy., and will burn lock-up clutch and 3-4 clutches up. '96 computer isn't compatible with '96 3-2 control solenoid.
1996: The 3-2 downshift strategy was changed to an on /off arrangement. The 3-2 downshift solenoid was changed to a 20-31 OHM solenoid, from the previous 10-15 OHM solenoid. The 3-2 control valve was changed to the second design valve. The easiest way to identify the valve is, the second design valve will fall out as soon as the solenoid is removed. The first design has a plug and retaining clip. TCC solenoid remains 10-15 OHMs, which is the same as the '95 arrangement. Has PWM stamped cast in pump. pump is the same as '95. Will not interchange with '95 unless changing 3-2 solenoid, valve body casting, and separator plate.
1997: Basically the same as '96.
1998-04 Uses woven carbon torque converter clutch material which is backward compatible, but not the other way. 1997 down TC clutch will burn up in later models because of the continuously variable slippage resulting from the later PCM's lockup programming.