904 will not upshift.

1972 Plymouth Duster

318, 904, 3.23.

Put a B&M stage 2 into the trans, now it will not shift into 2nd gear. :oops:

Got it up to about 30MPH and no shift, played with throttle/kickdown linkage and band.. Did not help.

Fluid was not burnt or black when drained, and it shifted properly without a kickdown linkage before I got into it.

What could be the cause? :pale:


EDIT: I cannot shift manually into 2nd gear.