chevy 93 6.5td no shift into any gear, 4L80E

[lolailando]

Was running fine for years. Suddenly transmission fail in the highway.
It feels in neutral. Linkeage is fine, but it doesn't even try to move as i shift to any gear. It does not hold in parking either.
2wd, no transfer case to worry about; driveshaft doesn't turn.
Fluid is red, no smell; I have tried adding 2 qt.

[DmaxMaverick]

The parking pawl is a mechanical engagement. So, if it doesn't work, it's mechanically broken internally (or otherwise disconnected), or the range selector shaft/bellcrank is broken. If you can feel the detents, it's more likely internal.