CHANGE: Beginning in the 1998 model year, General Motors added a new design “Bolt-On” bellhousing that is approximately 1/2″ deeper than the previous design. The best identification is the added bolt hole at the top of the bellhousing, as shown in Figure 1. The new design bellhousing is designed to accommodate a new 300mm torque converter, and in the 1998 model year was used only in the Firebird and Camaro. All other models in 1998 used the 298mm converter which required the bellhousing shown in Figure 2. Currently the 300mm converter is used in many more models.
REASON: To accommodate the new 300mm torque converter.
(1) BELL HOUSING – Now has an added hole at the top of the bellhousing and is approximately 1/2″ deeper to accommodate the new 300mm torque converter (See Figure 1).
(2) PUMP COVER – Now requires a stator shaft that is approximately 1/2″ longer to accommodate the new 300mm torque converter (See Figure 3).
(3) TURBINE SHAFT – Now is longer and has the “O” ring behind the splines, as illustrated in Figure 3, to accommodate the new 300mm torque converter.
None of the parts listed above will interchange with previous design parts and the 300mm torque converter must be used in the models they were intended, and 298mm torque converters must be used in the models they were intended for.
Figure 1: http://goo.gl/QsEff
This style bellhousing and the 300mm torque converter also require a new design turbine shaft and stator shaft that are approximately 1/2″ longer than the 298mm torque conveter models. The hot car tools like VAG K Can Plus 2.0 and AK500+ Key Programmer are also helpful for you to solve the problems.