snap-in connections instead of threaded. The original version of the transmission had a 27-spline input shaft (shared with the THM200C and 2004R) which was a common failure point. In 1984, the 700R4 designed for use behind Chevrolet small block V8s received a 30-spline input shaft similar to those found on TH400 transmissions and which also used a different torque converter than its 2.8 V6 and 2.2 L4 engines. Between 1984 and 1987, internal components, from the ring gear to the oil pump housing, were updated, ending with the auxiliary valve body for 700s manufactured after October 1986. In 1995, the 4L60E received a PWM-controlled lockup converter. The early designs simple on or off lockup function while the later design can regulate the apply pressure as to not feel the lock up occur. GM added a fifth solenoid to the valve body, called the PWM solenoid. In 1996, GM introduced a redesigned 4L60E transmission case that incorporated a bolt-on bellhousing and a six-bolt tail housing. This two-piece case style was first seen in 1996 and up model S-10 Blazer, S-10 pickup, GMC Jimmy, and GMC Sonoma with the 4.3 L engine. The majority of 1998 and later applications of the 4L60E were two-piece cases (i.e. a removable bellhousing). Both transmissions are the same internally. The non-PWM (1993-1994) style 4L60Es are not interchangeable with PWM-style (1995 and later) 4L60Es. Also in 1996, GM changed the 3-2 solenoid to a different style which makes it not interchangeable with any previous models. For the model year 1996 GM trucks, there were two versions of the 4L60E: one had a bolt-on bellhousing, the other did not. In total, there are nine different bolt-on bellhousings. The bolt-on bellhousings used on the 4.3 L V6 and 1996-2002 GEN I+ versions of the small-block Chevrolet V8 used the same bellhousing. These had one from 1996 to 1997 and then a slight redesign for 1998. The LSx engines used a longer one to accommodate a redesigned torque converter, commonly referred to as a 300mm converter, with a longer pilot nose (GM sells an adapter assembly for using the LSx 4L60Es when used with an early engine). There are two bellhousings for the Holden GM models. One for the Corvette drivetrain. One for the S/T platform with 2.2L and 3.8L engines. And finally, two for the S/T platform with the 2.8L, 3.5L and 4.2L engines (one used in 2002 and