His explanation is not clear.
He got water in Trans, We believe it came in though the vent tube on the top of the trans, He tried to cross a mud hole that was deeper than it looked and the Jeep was deep enough to get water in the floor boards. Afterwards it shifts (via the shifter) fine, But doesn't engage the gear. Basicly it would just rev and not go.
Changed the Fluid, filter and had it flushed (Which blew the main seal, replaced) and it will now drive up to 2nd gear, will not shift out of second.
So suggestions as to what the issue is, Besides the transmission is shot.