Yamaha 70ETLF 1989

Hey guys, my customer had a reverse problem (no reverse). He said he threw it in reverse with high rpms taking it off the trailer. The shifter is the old style with no Neutral lockout button. Anyway, I looked at it today. Nothing visually wrong. Shift cable is moving thru the full range etc.
Put it in fwd gear (engine off) turned prop counter and it engaged like normal.

The first time I put it in reverse and turned the prop, there was nothing? It just free spun. After shifting a few times it went into reverse and engaged, but I could turn it thru the gear (meaning the clutch dog wasn't holding it appears).

I brought the lower unit home and took the prop shaft out. The FWD teeth on the clutch dog are normal.
What I cannot remember now is, are the reverse teeth on the clutch dog the same as the fwd teeth OR are they suppose to be more squared?

If the squared teeth are normal, any ideas why it will break thru when I turn the prop by hand in reverse? Whether I turned it clock or counterclockwise, it did the same thing.

Here's the pictures of it.

Surprised no one could answer this.
Anyway, after inspecting everything I put it all back together. What I noticed after it was all together, the end play on the prop shaft was less than it was when I first took it apart.
Somehow the bell housing locknut wasn't tightened enough so it was allowing the reverse gear to be too far aft which didn't allow the clutch dog to engage fully.

All together and now I can't turn the prop shaft in reverse without turning the drive shaft. Will install back on engine in a few hours.