Does this transmission use vacuum control to shift smoothly? If so where can I find the unit and test it? I am asking because it shifts hard most of the time and the auxillary vacuum pump cycles for a while after start up. Just wondering if they are related. I do not hear any hissing noise to be able to find where vacuum leak could be. Thanks.

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If it ain't broke take it apart and find out why.

1983 300SD, 4 speed
1994 C280
1987 300TD wagon
1996 HD Road King

Ride in Peace Eric Peterson, Harley of Macon