Well just as I thought it was all coming together.... Should've known
better.

Here's what I have.
360 Chrysler Motor (early 70's) rebuilt in 1993 - FWC.
Owens "Hydrallic Reverse Gear" Transmission.

What I know:
The motor runs good, but does have a vaccuum leak, I am guessing right
now based on some quick digging that it is either the carb plate (nice wood
version. ) or from the intake gasket(s). No contamination of any fluids
in the motor from water or each other.

I have just replaced the tranny cooler with a larger unit and changed it
from the FWC side to before the motor on the raw water side. I did this
(chagned the cooler) cause the tranny fluid looked milky and not clear and
the cooler seemed to be leaking a little. I changed it to the RW side cause
it made more sense and that's the way I see most other boats.

So now my issue:

The tranny when I put it in reverse is bogging down the engine and
causing it to stall. Additionally, we have milky looking fluid again after
just changing it and running it for about 1 hour and sitting for 5 days.
Just changed the fluid again cause we found a vent on the tranny that could
have been taking in water (we have had some pretty heavy rains etc and the
vent was right in line with a leak in the deck).

Ideas?
I know the vaccuum leak is causing me to maintain a higher idle then I
like (1000 RPM vs 750/800), and it may be bad enough to cause the motor to
bog but not sure if this would be the issue for when I switch into gear.

Any ideas or has anyone even heard of this transmission? I believe it is
the original from the boat which was built in 1969, it was supposedly
rebuilt within the last year or two before I got the boat.

Sorry for being so long winded, but I would appreciate any ideas before I
start tearing out everything and rebuilding everything mechanical.

Thanks,
Mark.