ZF transmission oil change

[divedemo]

I have a 31 bertram with twin cummins 300's and zf trannys hooked up to them. I am wondering what is the best way to change the oil in the transmissions? Can I pull one of the hoses to the oil cooler and with a pump suck it out? Or are the two nuts on either side of the back bottom of the trannys the drain plugs and use those (that sure looks like a mess too) Also any idea of the model on those zf's. Thanks
Bernie
Tankwagon

[In Memory of Vicroy]

Bernie - I have been on the Tankwagon when John had her. As I remember you have ZF IRM 220A gears, probably 1.53: 1. Oil change interval is 1,000 hours and use SAE 30 straight motor oil.

Don't think you can pump the oil out from the cooler hoses. Now if you break a cooler hose or fitting it will all pump itself out, but not a good idea. The large nut on the bottom - think it's a 15/16th, is where you drain it.

UV

[divedemo]

And yes have already had one of those hoses break from rubbing up on the strainger coming up to the engine. A real mess.
Boat is still running great and caught two marlin and a bunch of large Dorados this year but not to many yellowfin.
Again thanks for the info and if your ever out this way you are welcome on the boat anytime

[Ironman]

Bernie: I have the same trannies(ZF220) I changed mine twice so far by sucking it out of the dipstickgets it all..
BTW almost bought that boat when it was "Lukuna" or something..in Newport beach.but .John beat me to it. So I repowered my 31 instead.
Wayne .
Seen you on allcoast?

[Brewster Minton]

I used a small tube hooked up to my oil pump out about 2 feet long and could stick it down the dipstick hole and vac out all the stuff in the bottom that way. I do not think removing the hoses is the way to do it or the nut on the bottom. I change the trany fluid every ten canyon trips or twenty day trips. I know they say every 1000 hr but I do it anyway. To be safe. I am not an expert. You should ask Bruce as he knows a great deal about this kind of stuff.