Torque converter
In or around '93-'94 the 4L60E came out.
You can't use just any 4L60 converter in a PWM 4L60E even though it will fit. It will work if you convert the trans to non PWM.
LS1's use a different input shaft so you can't put an LS1 4L60E converter in a non LS1 trans.

