Gear Box

sirgknight · Oct 10, 2004

I just purchased a used finishing mower from a private individual. When I opened the drain plug on the gear box to check the fluid condition and level the fluid started flowing out of the box and it was milky white. The box also seemed to be somewhat overfilled. The filler plug is "near" the top part of the gear box and the drain plug is "near" the bottom. My question is this: shouldn't the new gear lube be 90 weight gear lube and shouldn't the gear box only be filled to where it runs out of the drain plug near the bottom of the box? Isn't it possible to overfill this box and mess up the seals, etc?

mark777 · Oct 10, 2004

Yes, I am pretty sure your right. It should be filled with clean 80/90 weight and not over filled. The milky mixture is contamination from water. As I am not certain - It may ease your mind to contact the manufacturer for the correct capacity of your make and model.

jdmar · Oct 11, 2004

I hope I am not wrong here since this is how I fill my boxes....we are talking PTO boxes that make a 90 degree direction change right? /forums/images/graemlins/confused.gif
I use 80/90 wt. I fill mine until the oil just comes out of the FILL plug when the equipment is on level ground...so most of the box is full of oil.
Some people actually fill these boxes by pumping grease into them but I beleive most are intended for gear oil. A friends gear box went bad on an old Woods brush hog...the bottom oil/shaft seal leaked like mad. He fills with grease now and has noticed no problem in 3-4 years so far after his "fix." And the gear box doesn't leak out all its "oil" so fast now.

Peter

Soundguy · Oct 11, 2004

Most boxes I've seen have a fill hole.. and a -level- hole.. and NO drain hole.

You fill till oil comes out the level hole.

If you overfill.. you better hope your plug is vented.. and that it works, as seal failure can result otherwise.

Milky consistance is water emulsion. And I'd check with the manufacturer on what lube went in there. I've got 2 mowers.. one takes oil.. the other takes grease...

Soundguy

sirgknight · Oct 11, 2004

Yes, this is a PTO gearbox that makes a 90 deg turn. I checked the fill plug for a ventilation hole and there is none. There is also no evidence of any ventilation port or hole anywhere on the on the box. It seems to be a simple fill hole - drain hole operation. There's about one inch of space inside the gearbox above the fill hole. It would appear that the gearbox should be placed on a level surface and fill the gearbox until it runs out of the fill hole. This visibly would cover all of the gears and innner works and still leave about one inch of space above the lube.

sirgknight · Oct 11, 2004

I finally got it touch with a Farm Pro dealer and got the info on the mower. The gearbox should be filled to the top of the fill hole, leaving about an inch of air space above the oil in the box. The drain plug is simply used for draining the box. No ventilation. He did highly recommend that I drain the box then fill it with a pint of diesel fuel and hand turn the gearbox a few revolutions to get as much water out as possible. Then drain the gearbox, blow it out with an air hose, and fill it with a 75/25 mixture of 90 wt and Duralube. This is how their service department reconditions their gearboxes and says that they have virtually no problems with sufficient lubrication.

Soundguy · Oct 11, 2004

Yikes.. a non vent plug.. and it had water in it.. kinda makes you wonder how water got into a non-vented system...

Soundguy

sirgknight · Oct 12, 2004

I wonder that myself, but the fluid didn't look to be that contaminated. It had an oil consistency, it was just a little milky looking when it came out. It was bad enough though that I want to totally clean the inside of the gearbox and start over again with a good fresh lube job.

Soundguy · Oct 12, 2004

Probably not a bad idea.

Soundguy

86turbodsl · Oct 15, 2004

This is a symptom of equipment sitting outside all the time. The sun heats the gearbox, expanding the air inside, forcing some out, and when it gets dark, the cooling inside causes moisture laden air to enter the gearbox. It cools and condenses, then the moisture ends up in the bottom. Equipment sitting outdoors should have fluids changed more often than equipment that is always shedded.