[3100]

reverse clutch - not applying or slipping
piston and seal assembly - binding, cracked or leaking
inner seal - plugged orifice
clutch plates - worn friction or broken splines
snap ring- out of position
housing retainer and ball assembly - missing or out of position
springs-binding
reverse clutch fluid routing - fluid leak or restriction
driven sprocket support - leaking seal rings
Channel plate and gasket, and valve body gaskets and channel plate - porosity, fluid leak across the channels, misalignment, damage or fluid restriction
low and reverse band and servo - no apply or slipping
servo piston seals - leaking
servo pina and springs - binding
servo cover-broken, loose or leaking
low and reverse band - broken, worn or out of position
anchor pin - broken
fluid feed tubes - broken, bent, or plugged, missing or leaking seal rings
transmission case-porosity, fluid leak, or restriction
shift linkage-disconnected or misaligned
manual valve and link - disconnected or misaligned
#1 check ball- missing (no low band fluid)
fluid level - low
Fluid pressure low

all of them sound internal.............. But the smartest thing wound be as Phantom1492 said check for trans codes and post them here...