Water in TMC40P Gearbox - can it be saved?

[Toomuchboattime]

I was given, for free a 1984 Catalina 30. It was in rough shape, with about 2 feet of freshwater inside the boat for an undetermined amount of time. I've cleaned it and gotten to work on the engine and drive train.

The engine was water free, thank god- didn't reach the air intake and the oil was water free. The transmission wasn't so lucky. After the engine came back water free I got a little cocky. I checked the dipstick on the gearbox and it looked fine on quick glance, so I ran the motor and tried each gear at the dock. I know, I know... very very dumb. Shifted just fine until it would not long shift out of forward.

Killed the engine and noticed a clay like substance coming on the large holes of bell housing at 3 oclock. Opened the gearbox and pumped out a bunch of similar clay like goop. My guess is transmission oil whipped up into a froth mayo like substance by the transmission. Flushed it twice with new ATF, and with a little massaging, it started shifting smoothly again.

My assumption based on the goop in the bell housing is that I over pressurized the gear box, the oil mixture forced its way out through the seal around the shaft that goes into the bell housing and the flywheel started tossing the mess all over.

Also, my guess is that standing water inside a gearbox is bad to quite bad and would likely cause significant corrosion, but that said... it seems to be working fine.

I guess my question is this: do I order a new one simply based on the fact that without a full tear down there's no way to know how much damage was been done, or, do I replace the upper seal, clean out the bell housing and see how much use I can get out of it? Or rebuild without replacing? Any advice is appreciated.

[FPNC]

Your transmission is no longer reliable. For the long term reliability, it is best to replace it with the same transmission. The cost to rebuild the transmission to spec would be close to the price of a replacement transmission.

[Toomuchboattime]

I thought this might be the case. Thank you for confirming.

[skipperpete]

Take FPNC’s wise advice.
One of my neighbours had a similar flooding experience and is currently looking at repairing extensive corrosion damage in the flywheel housing, the starter motor was the first problem, unrepairable so a new one was installed and the engine was eventually started but the corrosion had destroyed the drive plate, rear main oil seal and front and rear gearbox oil seals as well as the surfaces that those seals run on. He has oil coming out of the timing pin hole in the flywheel housing…like muddy sludge and is in the process of sourcing “Speedisleeves”and seals…. This might be a bit futile, to do the hurth rear seal he has to strip the entire gearbox and might well encounter what FPNC mentioned regarding the cost and reliability factors.