Repurposing oil.

[Rickg5106]

Hello All,
I have a Husky ZTurn with a Briggs Vangaurd engine. Both the trans and the motor use 20W50 motor oil. It’s getting time to do the fluid change and I was wondering if there was any reason for not using the old trans oil in the motor. The trans has not been over temped, it’s well filtered and there shouldn’t be any degradation of it lubrication properties at all. Other than lubrication of some gears the only thing it was used for was an incompressible fluid. Am I on the wrong track here? Let me know.
thanks

 

[Warstud]

Hello All,
I was wondering if there was any reason for not using the old trans oil in the motor.

Yea....Trans oil is not motor oil. Both can be re-purposed by recycling.

 

[ctechbob]

If the hydrostatic is anything like the Tuff Torq in my Cub Cadet that oil will drain with plenty of metal in it that you don't want running in your engine. Fresh oil all the way around, recycle the old.

 

[RooflessVW]

Yea....Trans oil is not motor oil. Both can be re-purposed by recycling.

The trans and motor take 20W-50.

 

[RooflessVW]

If the hydrostatic is anything like the Tuff Torq in my Cub Cadet that oil will drain with plenty of metal in it that you don't want running in your engine. Fresh oil all the way around, recycle the old.

Exactly.

 

[#18FAN]

That drain pan from them hydrostatic will have glitter in it I promise you that.

 

[stangguy]

I agree that the transmission oil will have metal in it. Also, if the trans oil is good enough to use in the engine, it sure wouldn't need to be drained out of the trans.

 

[Rickg5106]

Thanks all for the reply’s.
To clear up some of the above, the hydrostatic drives have screw on filters.
Both the drives and the motor use standard 20W50 motor oil.
All hydraulics (including hydrostatics) typically have to be micron clean for any kind of operational longevity.
I agree that if it’s clean enough to run in a motor, it shouldn’t be changed but it’s been run for 3 years, none commercially, and I figure it’s time.
I also know that most of the “dirt” in used motor oil is due to combustion byproducts. If the oil hasn’t been overheated, there’s really nothing wrong with it ( other than the “dirt”).
There isn’t any combustion in the drives but the possibility of initial wear is real, but should have been caught by the filters.
But, on the other hand, lubrication is so good nowadays that nothing really ever touches anymore. I have personal experience with this in an aviation setting where we couldn’t get rings to seat after a rebuild until we ran straight weight mineral oil.
I also understand that filtration is a compromise between flow and efficiency so the possibility of something getting by is real.
I was just wondering if anybody had had any thoughts about repurposing one to the other.
Thanks all for the comments, I appreciate it.

 

[OZHSV]

What’s 20w-50 cost in the States...$5-10 a jug? I without pretending to know the how the trans fluid would hold up, from a financial point of view, I don’t know why you’d even consider it. Just get some fresh stuff, I’d only ever repurpose old oil to the recycling centre.

 

[ironman_gq]

What comes out of those transmissions won't be 20w-50 anymore, it will almost definitely have sheared down after 3 seasons.

 

[Kuato]

What comes out of those transmissions won't be 20w-50 anymore, it will almost definitely have sheared down after 3 seasons.

My thought also.

OP if you're thinking of doing this, do yourself a favor beforehand and get a UOA. Then you will know for sure if you want to filter that oil and put it back into the engine.

 

[Rickg5106]

What comes out of those transmissions won't be 20w-50 anymore, it will almost definitely have sheared down after 3 seasons.

And that is what I thought as well but figured I’d make the case for it and see where the thread went.

 

[spasm3]

If it's not good enough for the transmission anymore, it's not any good for the engine.

 

[Mr_Joe]

If I have ‘clean’ drain oil, that’s oil changed that has few hours on it, I may use it as ‘winter weight’ bar oil for the chainsaw.

With regular, drained oil, I use some as lube on my log splitter beam. I may use some as tool wipe down/preservative & rust prevention. After that I use a bit to get the brush pile burning well.