I agree, the B2 piston is broken or the seal blown. It can be repaired without trans removal. There is a modified piston now with a strengthened core and a totally different seal.

The piston breaking is often a result of higher than spec modulator pressure. This is often done to deal with flairs into 4th gear. The 83 trans has a number of modifications that improve the quality of shift. If you decide to rebuild it be sure that you have the mods done.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician