Moderator note 3/14/2022: This thread was written by the late Frank Cahall of Cahall Performance Transmissions of Newark Delaware. His wife Gail Cahall is still running the business as of 2022. Some people (including Frank) make a big deal about the 3-2 downshift solenoid change for '96; others have swapped and not had a problem. I am preserving this thread for the content it contains.
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None of the '93 -'97 4L60E's are directly interchangeable, except '93 and '94!!! Here's a list of yearly differences that will show you why. Yes, some years will fit in others and may not even throw a code, but there will be an issue in the long run. The big issues become forced 3-2 downshifts, converter lock-up issues, and burnt lock-up clutches. When a converter clutch cause it to lose lock up, the 3-4 clutches, in the transmission will soon follow because the 3-4's need lock up to keep them cool while cruising in overdrive.
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 the front pump. 1 piece TCC control valve in the valve body. The plate has holes in the plate, marked in the 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 converter clutch. It has a 12-pin case connector, an extra wire in the transmission to the computer harness, and a different computer to control the new PWM circuit. Has PWM cast in the front pump? Front pump internal passages are different to match the new TCC strategy. 2 piece TCC control valve in the valve body. Has holes in the plate, marked in the diagram below. 1st design 3-2 valve. 12-pin case connector. '94 computer won't recognize the new TCC strategy., and will burn the 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 TCC control 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 the pump. The pump is the same as '95. Will not interchange with '95 unless changing 3-2 solenoid, valve body casting, and separator plate. Has holes in the plate marked in the diagram. '94 or '95 computer will not accept the 20-31 OHM 3-2 solenoid and will throw an SES light and throw the transmission into limp mode. Some less knowledgeable builders will swap the solenoid so the computer will see the correct resistance, but the valve itself then causes downshift issues. If only the solenoid is changed, it will result in a 3-2 downshift cut loose. In other words... a 3-neutral-2 downshift. Speedo moved to the passenger side of the tail housing but easily changed.
1997: Basically the same as '96.
Frank
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None of the '93 -'97 4L60E's are directly interchangeable, except '93 and '94!!! Here's a list of yearly differences that will show you why. Yes, some years will fit in others and may not even throw a code, but there will be an issue in the long run. The big issues become forced 3-2 downshifts, converter lock-up issues, and burnt lock-up clutches. When a converter clutch cause it to lose lock up, the 3-4 clutches, in the transmission will soon follow because the 3-4's need lock up to keep them cool while cruising in overdrive.
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 the front pump. 1 piece TCC control valve in the valve body. The plate has holes in the plate, marked in the 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 converter clutch. It has a 12-pin case connector, an extra wire in the transmission to the computer harness, and a different computer to control the new PWM circuit. Has PWM cast in the front pump? Front pump internal passages are different to match the new TCC strategy. 2 piece TCC control valve in the valve body. Has holes in the plate, marked in the diagram below. 1st design 3-2 valve. 12-pin case connector. '94 computer won't recognize the new TCC strategy., and will burn the 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 TCC control 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 the pump. The pump is the same as '95. Will not interchange with '95 unless changing 3-2 solenoid, valve body casting, and separator plate. Has holes in the plate marked in the diagram. '94 or '95 computer will not accept the 20-31 OHM 3-2 solenoid and will throw an SES light and throw the transmission into limp mode. Some less knowledgeable builders will swap the solenoid so the computer will see the correct resistance, but the valve itself then causes downshift issues. If only the solenoid is changed, it will result in a 3-2 downshift cut loose. In other words... a 3-neutral-2 downshift. Speedo moved to the passenger side of the tail housing but easily changed.
1997: Basically the same as '96.
Frank