Oil loss when filling the lower transmission unit

[Jerry_NJ]

I must have noticed this before, but it bothered me this time. I opened the lower, drain, on the lower transmission with the top plug in place. some oil started leaking out. I quickly screwed in my pump hose and the leak stopped. I then removed the top plug and pumped oil in until it started to flow out the top hole. I replaced the top plug and put in the lower plug as fast as I could when the pump line was removed. I still lost at least a ounce or so of oil. Is this a problem? I think the case colds about 10 or 12 ounces of oil.

That is correct, I did not change the oil, I was just trying to check to be sure the case is full. The engine has only a few hours on the oil as I didn't use the engine much last year.

 

[F_R]

Re: Oil loss when filling the lower transmission unit

Yeah, you gotta be quick. Everybody loses a little bit. If you suspect you lost too much, use a pump type oiler can to top it off at the top plug. Patience is the key, if you try to put it in too fast it will belch back out at you.

 

[Fed]

Re: Oil loss when filling the lower transmission unit

If you're right handed when you remove the pump line put your left thumb over the hole then do the quick change with the plug in your right hand. You won't lose much that way.

 

[sschefer]

Re: Oil loss when filling the lower transmission unit

Actually, the name of the game is to lose an ounce to allow for expansion. You're fine.

 

[Jerry_NJ]

Re: Oil loss when filling the lower transmission unit

Great, I did it correctly in spite of myself I did try to squirt some in the top hole after putting the bottom plug on. The pump put out too much at once and it just "bounced" back out. An oil can could win that battle, but the "Captain's" point about room for expansion works for me.

 

[1kruzer1]

Re: Oil loss when filling the lower transmission unit

The proper oil fill is level with the top vent plug. The manufacturer has already allowed for expansion with the plug position relative to the shaft bearing. Here's an "unorthodox" trick:
Fill the gearcase in the normal verticle motor position. When it's full, don't remove your pump just yet. Tilt the motor up and turn it so the vent and fill plugs face up as much as possible. With many motors you'll now be able to pump in a bit more oil. Pump in the oil, remove the pump, and quickly install the lower plug. Now lower the motor back to the normal verticle position and allow the excess oil to drain out of the top vent plug. When it completely stops draining the oil will be at the proper level at the top plug. Make sure you leave the top plug out and allow the oil to drain back to this level! You do NOT want to leave it over filled or you can blow out a seal.

Another method that works is to fill the gearcase normally until the fluid starts to come out the top plug. Now put the top plug in VERY LOOSLEY, maybe a little over half a turn. You just want to catch enough thread so the plug will hold itself in place. Yes, it will leak, but it now leaks slowly. You can now pump in an extra couple shots of lube, remove the pump and quickly install the lower plug. Remove the top plug and allow the oil to completely drain down to the level of the top plug.
Remember, both of these methods initially result in an over filled gearcase. You MUST leave the top plug out and allow the oil to drain down to the proper level before finally putting the top plug back in tight. Good luck!

 

[1kruzer1]

Re: Oil loss when filling the lower transmission unit

The proper oil fill is level with the top vent plug. The manufacturer has already allowed for expansion with the plug position relative to the shaft bearing. Here's an "unorthodox" trick:
Fill the gearcase in the normal verticle motor position. When it's full, don't remove your pump just yet. Tilt the motor up and turn it so the vent and fill plugs face up as much as possible. With many motors you'll now be able to pump in a bit more oil. Pump in the oil, remove the pump, and quickly install the lower plug. Now lower the motor back to the normal verticle position and allow the excess oil to drain out of the top vent plug. When it completely stops draining the oil will be at the proper level at the top plug. Make sure you leave the top plug out and allow the oil to drain back to this level! You do NOT want to leave it over filled or you can blow out a seal.

Another method that works is to fill the gearcase normally until the fluid starts to come out the top plug. Now put the top plug in VERY LOOSLEY, maybe a little over half a turn. You just want to catch enough thread so the plug will hold itself in place. Yes, it will leak, but it now leaks slowly. You can now pump in an extra couple shots of lube, remove the pump and quickly install the lower plug. Remove the top plug and allow the oil to completely drain down to the level of the top plug.
Remember, both of these methods initially result in an over filled gearcase. You MUST leave the top plug out and allow the oil to drain down to the proper level before finally putting the top plug back in tight. Good luck!