The 4L30E is a 4 speed automatic by General Motors. It is used in Chevrolet, Cadillac, BMW and Honda. The most common parts sold to rebuild or repair this unit are the Master Kit, Brake Band and Filter. It is suggested the Valve Body Kit, Thrust Washer Kit and Bushing Kit also be purchased and installed for a more complete rebuild.
Here is some more information on the parts mentioned in this posting.
The filter and filter kits are different for BMW and the same for the rest of the vehicles. The brake band, bushing kit, thrust washer kit and valve body kit are the same for all years and vehicle makes.
For the most part all parts are compatible across the line for most commonly parts sold for a rebuild. There are some exceptions such as the filter and there are some variations on hard parts.