Standard vs Synthetic Oil in differential

[MParr]

This thread is starting to veer off in an entirely different direction.
The OP was specifically talking about the oil in the hydros of his Hustler Raptor FlipUp.

 

[bertsmobile1]

Yes knowledge comes from years of experience or reading. I'm not claiming to be an expert but years of reading various sources (mostly bobistheoilguy as it is actually run by a chemical engineer of some kind and has a great FAQ section) I wanted to make sure I wasn't going crazy since almost everything you said went against everything I had ever read except for myths from old farmers or mechanics. I tried my best, and double checked my sources of information, but I can't make you do the same.

Well Rocket,
I had bit of spare time today as the phone is down so no phone calls.
I re-read this whole thread and even your go-to Bob, chapters 1 through to 6
Nothing there that is any different to anything I posted other than the words we used to say it . "Use what is recommended by the makers & replacing a std oil with a synthetic MAY do nothing other than cost more money"
I really think you have the idea that I am anti-synthetic and thus read what I post in a highly subjective mannar.
Add to that being in OZ what gets written is as I would do for an Aust reader, we do not have NASCAR down here ( seemed to bother one of the cross posters ), but when Mobil was trying to convince everyone to buy their much more expensive synthetic oil they pushed the F1 heritage very hard so that is what comes to mind first.
So perhaps you would find "the existing synthetic oils from avaition were modified to meet the demand situations of motor racing where standard oils were found wanting and money was not a problem " more pallitable to your USA thinking.
Other that that then you are welcome to consider me as a synthetic hating blithering idiot.
But try and find the answer to "why does the oil remain between the slipper bearing and the journal on a big end and not get totally pushed out at BDC on the power stroke " .
Go to some of the piston ring makers web pages ( total seal is good ) and read about how a piston ring actually works and then go back to your trusted informers and ask them to explain " why the oil stays behind the ring and not just get pushed out "
And for mower specific applications
"why does oil flow between the con rod & journal on a full splash engine when gravity and momential inertia should have it all tossed away and not flow between the very close spaces "
And ask those whose opinion your trust
"why does the oil in a hydro drive push the pistons and not all escape down the sides of the pistons ( remember there are no piston rings to make a seal ) or between the cylinder block and kidney plate where there is no seal either "
And FWIW there is nothing stopping the oil going directly from the inlet to the outlet holes in the kidney plate either as previously mentioned one plate 2 to 6 slots with oil coming in one slot under pressure and going out the other with no back pressure to prevent the flow which is how most hydros fail.
Troll through the posts here and you will find lots of photos of failed kidney plates.

And I was a member of the ASTM from 1972 through to 1994 as I had to be able to certify goods destined for the USA market and the USA would not accept the Aus NATA certification.

 

[MParr]

Well Rocket,
I had bit of spare time today as the phone is down so no phone calls.
I re-read this whole thread and even your go-to Bob, chapters 1 through to 6
Nothing there that is any different to anything I posted other than the words we used to say it . "Use what is recommended by the makers & replacing a std oil with a synthetic MAY do nothing other than cost more money"
I really think you have the idea that I am anti-synthetic and thus read what I post in a highly subjective mannar.
Add to that being in OZ what gets written is as I would do for an Aust reader, we do not have NASCAR down here ( seemed to bother one of the cross posters ), but when Mobil was trying to convince everyone to buy their much more expensive synthetic oil they pushed the F1 heritage very hard so that is what comes to mind first.
So perhaps you would find "the existing synthetic oils from avaition were modified to meet the demand situations of motor racing where standard oils were found wanting and money was not a problem " more pallitable to your USA thinking.
Other that that then you are welcome to consider me as a synthetic hating blithering idiot.
But try and find the answer to "why does the oil remain between the slipper bearing and the journal on a big end and not get totally pushed out at BDC on the power stroke " .
Go to some of the piston ring makers web pages ( total seal is good ) and read about how a piston ring actually works and then go back to your trusted informers and ask them to explain " why the oil stays behind the ring and not just get pushed out "
And for mower specific applications
"why does oil flow between the con rod & journal on a full splash engine when gravity and momential inertia should have it all tossed away and not flow between the very close spaces "
And ask those whose opinion your trust
"why does the oil in a hydro drive push the pistons and not all escape down the sides of the pistons ( remember there are no piston rings to make a seal ) or between the cylinder block and kidney plate where there is no seal either "
And FWIW there is nothing stopping the oil going directly from the inlet to the outlet holes in the kidney plate either as previously mentioned one plate 2 to 6 slots with oil coming in one slot under pressure and going out the other with no back pressure to prevent the flow which is how most hydros fail.
Troll through the posts here and you will find lots of photos of failed kidney plates.

And I was a member of the ASTM from 1972 through to 1994 as I had to be able to certify goods destined for the USA market and the USA would not accept the Aus NATA certification.

I’m pretty much in agreement. A hydrostatic transmission is not and engine. Therefore, it really doesn’t matter whether you use a synthetic oil, blend or conventional oil in the hydros. A 20W50 conventional oil with high ZDDP content is probably going to be the best bang for the buck. Most of those oils will be geared for classic cars or racing engines. Why? Because, some 20W50 oils have the ZDDP and Phosphorus content lowered to prevent the cooking of catalytic converters in cars.
Mobil 1 15W50 is high in ZDDP and Phosphorus. Valvoline VR1 20W50 is a really good choice and is much cheaper than Mobile 1 15W50.

 

[DK35vince]

An engineer at Briggs told me that conventional oil is needed during break in to seat the rings properly. .

My Briggs Vanguard 37 hp with oil guard came from the factory with synthetic oil in it.

 

[bertsmobile1]

I’m pretty much in agreement. A hydrostatic transmission is not and engine. Therefore, it really doesn’t matter whether you use a synthetic oil, blend or conventional oil in the hydros. A 20W50 conventional oil with high ZDDP content is probably going to be the best bang for the buck. Most of those oils will be geared for classic cars or racing engines. Why? Because, some 20W50 oils have the ZDDP and Phosphorus content lowered to prevent the cooking of catalytic converters in cars.
Mobil 1 15W50 is high in ZDDP and Phosphorus. Valvoline VR1 20W50 is a really good choice and is much cheaper than Mobile 1 15W50.

Sort of
Again it depends upon what the hydro was designed to run
Most MODERN ones will be fine
We popped some synthetic into the Hydro on the 1960 Oliver 100Hp tractor and the results were not good.
Now it is an old tractor and thus the hydro drive has done a bit of work so it was probably in need of an overhaul so I won't blame the oil
But it was working on strait 50 and would not budge on 15W60 which was recommended by the tractor shop
So $ 3000 latter it is back in the tractor & running quite happily on Penrite Harley oil 30W70
Apparently this was an add on unit rather than the intergrated one that shared the gear box oil with the hydro drive

 

[slomo]

Oh and here is another chart just like most engine manufacturers have in their owners manual... proving that viscosity is not as critical as most think.

Anyone on Earth agree with this?

And a couple charts now prove everyone wrong?

 

[MParr]

The OP has a Hustler Raptor FlipUp. 20W50 is recommended.
Tuff Torque are usually found on John Deere Zero Turns and many different brands of lawn tractors.
Here’s their chart. https://tufftorq.ordertree.com/media/promo/TuffTorq/Fluids and Lubricants.pdf
Parker wheel motors are another option.
Qualified Oils Number of hours
Parker HT-1000TM (P/N 406030) 1U.S. Gal. (3.8L) 1000
Castrol Syntec 5W50 500
Amsoil AW ISO 68 500
Shell TTF-SB 500 Other* 250

 

[bertsmobile1]

Funny enough when I posted that the numbers on the bottle just tell you how fast the oil will drain back into the sump many took exception, when in fact, it was a fact
The numbers on the bottle are determined by the time for fixed volume of oil to pass through a fixed size hole in a device of fixed proportions under the effect of gravity alone at a specific temperature
Now there are some variations as some times we measure the volume over a fixed time, but the net result is the same, it is the drain back rate at different temperatures and not the flow rate under pressure .
Oh but I forgot I am a blithering idiot who knows nothing .
Just about all of the testing done on oils is there to compare one oil ( or oil blend package ) to another and not how the oil will behave inside your engine, unless some one can find a place where the engine has some ball bearings ( usually 3 ) mounted in a fixed plate jamed into a rotating plate till the plate stops spinning .
And this applies to most product testing
How many collisions are a vehicle slamming dead square on into a solid wall that has absolutely no give and the vehicle is prevented from recoil .
A test done to see what effect design & materials changes made
So we do a host of tests to oil
I can not seem to remember a place in any engine where the oil is heated till the fume bursts into flame .

Having said that we can use the numbers , but that is a secondary co-relation because we have found out by actually running the oil in an engine or a hydro, that an oil that behaves like this under the effect of gravity ( viscosity) will function in a particular way in our device that is desireable
Much like using a hardness test which is not destructive to determine the tensile strength of steel which is very commonly done because testing hasfound that in most cases a steel with a hardness of X will usually exhibit a tensile strength between A & D .

And as an aside, at one time I challenged an equipment makers as to why they specified an engine oil when a transmission oil would do the job a lot better
His answer was interesting
"Firstly is is cost, the engine oil costs a lot less and is just good enough to do the job"
Secondly people do not understand viscosity and very few realize that the quoted viscosity numbers on transmission oils different to engine oils & we worry that they will put 30 transmission oil into a box that requires a 70 transmission oil so to avoid confusion & warranty claims we specify engine oil in the transmission "