HBW 10-2r rebuild or replace?

[Mercator30]

1976 Sailboat has total of 65 (for real) running hours with original running gear. After several hours of cruising with the engine and returning to dock, noticed atf fluid thrown in an arching pattern from the rear of the Hurth. Checking fluid found it low and had been full before leaving dock earlier.
Today I filled the Hurth to the proper level, and ran the boat at the dock in gear with a paper towel under the transmission. A spray pattern appeared at the rear seal and a large wet spot at the front of the tranny. Can't determine if the rear or front is leaking but either way I am assuming the transmission has to come out. I have full overhead access to the engine and tranny (pilot house floor. So assume it wont be hard to pull?
But my most important question is should I rebuild? or at least replace the front and back seals? Are bearings easy to replace? i.e. do they require reshimming or can old shims be used when replacing just bearings? The Hurth shifts excellent. I dont know the normal noise levels of this Hurth but it is noisy, like bearing noise? Maybe normal. Just seems like such a waste to not get some miles out it.

[DougR]

43 year old boat and only 65 hours on the drive train......probably there has been some rust develop on both input and output shaft and caused the seals to fail.

Replacing the input shaft seal is an easy job.....pull the seal carrier off, swap seals and replace the carrier with a new gasket.

Unfortunately replacing the output shaft seal is not so easy because the output
shaft flange is integral with the shaft, and that shaft carries the clutch pack. So you have to split the case and remove the shaft, then disassemble the clutch assembly from the output shaft to get to the seal.

Not an impossible job for someone with some tools and the aptitude. Probably a good idea anyway to check whether there is any pitting on the bearings or bearing races.

DougR

[Mercator30]

Decided to "bite the bullet" and bought a new ZF12-m to replace it. May split the case on the old one, inspect it for rust and determine if I can repair or not for a spare.
Ya, the original owner spent his life building the boat since the 70's and got to sail in her once thanks to a gallant effort by his son. I expected some "cobwebs" to show up and this is the biggest one yet. Thanks for the advice Doug..