[Richard]

Mine leaked too after the rebuild.

I took the unit back out, and I saw a scored area on the output shaft that perfectly aligned with the seal lip. I don't know how I missed that on the first go round. The score was too deep to polish out, but the bore where the seal resides had enough extra length that I was able to install a new seal and seat it 1/8 deeper than flush which placed the seal lips on good clean shaft areas.

Having done this multiple times now, here is THE DRILL for getting the unit out with the least fuss and muss.
1. Detach the drain line to the hydraulic tank and drain into a two or more gallon container. Then detach the hyd line from the motor to the OHLA.
2. Loosen the two bolts that hold the hyd motor to the OHLA
3. Remove the four bolts that hold the OHLA to the stand.
4. Carefully move the assembly back and angle it to give access to the front of the fan.
5. Remove the fan bolt, and leave the fan in the radiator shroud.
6. Use rope or strap to secure the Hyd motor to keep it from falling.
7. Remove the two bolts, and separate the OHLA from the Hyd motor.
8. Grunt loudly and lift it out of there.

Reverse steps for reinstallation.

There are other ways of doing it, but this sequence avoids having to reach through the fan and fan shroud to deal with the bolt securing the fan to the shaft.