Th400 no engine braking in 2nd gear
 

Anyone have experience with a broken plastic servo piston causing no engine braking in 2nd gear?

Was the fix as easy as dropping the valve body and replacing the servo piston and sealing ring with a metal one?

It's in my sons 1986 c20 Scottsdale with a 350/th400 combo and only 56,000 original miles.

Thanks!