You probably don't have to worry about it. I see them go much further and have no issues. When you need a project, there ya go.

Tomplum,if in the future,two questions. Could I suck the oil out thru the filler plug,as I couldnt get all the oil out,get what I could and then replace the amount I removed with the same factory oil,although I am mixing some old with the new,wouldn't that still be helpful. Next question, After looking at a drawing of the housing,drill and tap a drain hole,near the bottom,or is the housing too thin to tap. Might seem like dumb questions,but you never know till you ask. John

Most likely your unit is "sealed for life" not intended to be change. Many hydros recommended against changing as the possibility of contamination was greater than the benefit of changing - after all, there is no internal combustion taking place in the hydro as in an internal combustion engine which is the prime reason for changing.

Walt Conner

You are right,as thats what the factory states,but the oil is black,looks like engine oil with 20K miles on it. Am sure their interests are in selling new mowers and transmissions. Thanks

"...after all, there is no internal combustion taking place in the hydro as
in an internal combustion engine which is the prime reason for changing"

With respect, that is true for engines but there's no internal combustion in manual or automatic transmissions or in transfer cases and differentials. Changing lubricants in those assemblies is as important as changing lubricants in engines.

Along with the degradation of lubricants by combustion other important reasons for changing lubricants is the degradation of lubricants by HEAT, pressure, and working shear (as in gear boxes and differentials).

In the case of LT-GT transmissions the oil dies from heat. Changing fluid in hydrosatic transaxles that some people regale as problematic and substituting synthetic oil for the OEM (cheap) fill can result in long and reliable service if you do it BEFORE you abuse the transaxle.

Think you are getting a little wild here, in owning cars and trucks for 69 years I have never changed gear box or differential lub. . When a mfg. says the chance of damage to their hydro is greater changing than just running, they likely have a reason.

Walt Conner

FWIW, last year bought a Craftsman 917.986450, 26HP Kohler, 54" deck, Hydro Gear G7-BCBB-etc.... trans. Sears manual clearly stated that the trans is a sealed unit, no maintenance required. Went to the Hydro Gear website and downloaded the manual. They recommend changing oil and filter at 40 hours and at 400 hour intervals thereafter. Sears, will, however, sell you the trans filter for over three times what the OEM gets. :-)

Have read many posts here and on other sites about changing oil in trans with no fill plug, pull and invert and let drain for a few days. I actually did that for a neighbor a couple years ago and it rejuvinated a slow moving machine.

I agree with Walt on chaning oil in manual trans and rear ends. I've "only" been owning cars, etc. for 50 years, top them off and don't worry about it. Here on the farm we had Farmall tractors from the 40's that probably had original trans and rear end oil plus "top off's." I changed the oil in the trans of my GT5000 after ten years, what a waste of two gallons of oil! Had I drained it into a clean container, would have put it back in, yes, it was that clean.

Hydro's run much hotter and heat degrades oil, that's the reason they have cooling fins and fans. Keep the fins clean and the fan unobstructed and functional. I agree with Lurker about using synthetic oil in them.

OP, if you want a "warm tummy" feeling about your machine, this fall, after mowing is done, pull the trans, (sounds worse than it is) drain for a couple days and refill. You'll have to purge it to get rid of air and add oil until it's full. tomplum also makes a valid comment about a lot of these machines go for a long time.

Wasn't it Mownie who said that the reason that drain plugs are no longer provided was the choice between a beverage holder or trans drain plug in order to meet the price point? Anyone seen him around lately, BTW?

I'm also sure that Sears, etc. withholding trans. OEM's recco's has nothing to do with the "planned obselecence (sp?) society we're in.

Be well,

Ev

Thanks to everybody who gave me answers. I was a mechanic for about 5 years out of high school,and we never changed oil in transmission or rear end until the automatics came and then we serviced them,although I did change oil in my souped 42 fords(drag racing,most fun I ever had in 1950) transmission about every 2 months,as speed shifting to second gear did strip cluster gears. I sucked near 50 ounces of nasty oil out of my hydro (it was operating ok,but with 250 hours)The dirty oil didnt feel like oil,I replaced it with said amount of new 20-50, that really picked up power and after 3 hours on it,checked it and after mixing with the old, oil felt good and was dark gray,so I changed the oil a second time and after 2 hours run time,it was a light gray.Will probably change it every 75 or so hours,since it only takes 45 minutes and $8 for a single change.(will do the double) Question; if after I suck all the oil I can get,i stared it up and let it run for 30 sec or so,would the oil from the pump empty in to the crankcase? Wont try it until I get an answer from someone who knows the hydros. Thanks to this smart board,my cub might last a few more years than cub had planned. John