I have a 1970 Mercedes 300 SEL 6.3. When shifting from park to reverse, or drive, it engages hard. Hard enough to jerk your head back if your not expecting it.
The idle is normal and there are no vacuum leaks I can find. The car has been sitting for about five years, and had leaked a few quarts of transmission fluid. Upon refilling and initial inspection this problem became apparent. Does anyone have any suggestions on what might cause this? Anything I can do without tearing into the valve body? Thanks in advance

Beladona!