Who's using RLI 75W-90 in their manual gearboxes?

[Yuk]

Originally Posted By: tdi-rick
Quickly, anything that is dual rated is safe for yellow metals.
If in doubt, look for the copper corrosion test results in the PDS. Anything with 1a or 1b is ok.
Even most straight GL5's these days use buffered sulphur compounds which are non reactive.


If I understand you correctly, the fact that RLI's Bio-Synthetic 75W-90 Gear Lubricant is dual rated as both GL-4 and GL-5, and has a copper corrosion test result of 1B means that this lubricant should be completely compatible with service in a manual transmission?

It also appears to me, that the specs further support the use of BioSyn 75W-90 in MTs because the BioSyn has a viscosity of 15.7 cSt and not 18 cSt, like rear end lube.

 

[SubLGT]

Originally Posted By: Yuk
................It also appears to me, that the specs further support the use of BioSyn 75W-90 in MTs because the BioSyn has a viscosity of 15.7 cSt and not 18 cSt, like rear end lube.


I would think that Amsoil MTG 75W90 GL4 transmission oil, with a viscosity of 14.7, would shift a lot easier at -25C.

 

[tdi-rick]

Originally Posted By: SubLGT
Originally Posted By: Yuk
................It also appears to me, that the specs further support the use of BioSyn 75W-90 in MTs because the BioSyn has a viscosity of 15.7 cSt and not 18 cSt, like rear end lube.


I would think that Amsoil MTG 75W90 GL4 transmission oil, with a viscosity of 14.7, would shift a lot easier at -25C.


really does depend on the VI.

 

[SubLGT]

Brookfield Viscosity, at -40degC:

RLI: 115,000

Amsoil: 43,595

 

[tdi-rick]

Originally Posted By: SubLGT
Brookfield Viscosity, at -40degC:

RLI: 115,000

Amsoil: 43,595


that'd make a difference

 

[Yuk]

Originally Posted By: SubLGT
Brookfield Viscosity, at -40degC:

RLI: 115,000

Amsoil: 43,595


What is the practical, felt difference between 115,000 and 43,595 @ -40ºC? Are we talking a spoon in peanut butter vs a spoon in water?

 

[Tempest]

Originally Posted By: SubLGT
Brookfield Viscosity, at -40degC:

RLI: 115,000

Amsoil: 43,595

 

[bruce381]

more like pudding to pancake batter

 

[JoeFromPA]

FYI - Per a recommendation on BITOG, I just swapped AMSOIL 75w110 into my 2008 Subaru Legacy GT transmission/front diff.

This was to replace the stock fill.

I'm not yet ready to do a full write-up on it. But at 50 degrees fahrenheit, shifting is [censored] near identical to stock (need more experience here and with a little colder). At operating temps, shifting seems the same...maybe a tad smoother. Gear whine upon engine braking seems greatly diminished and the drivetrain overall seems to mesh smoother. Again, this was based upon a fairly minimal driving time. It's my wife's car, but I'm going to drive it into work within the next few days and write up my impressions (I drive 32 miles each way, about 20 miles highway and 12 miles stoplights).

At room temperature to 55 degrees, it moved like hot maple syrup. It poured easily into a funnel, but went down the funnel slowly. Hope that makes sense.

Joe

 

[Yuk]

Originally Posted By: bruce381
more like pudding to pancake batter

I didn't know if anybody was going to take me seriously, with the whole food analogy thing. I do think though, that making real life viscosity comparisons can help when trying to put these numbers into perspective.

Bruce,
If you are not just pulling my leg, it would seem to me that the viscosity difference between pudding to pancake batter is not that great. Is it?

 

[Tempest]

Don't know where this is on the food scale, but ATF's have -40C limits of 10,000 - 20,000 cSt as a reference.

 

[Gary Allan]

One pours when you tilt the mixing bowl. The other just sits there and (maybe) wiggles.

 

[MolaKule]

What I have experienced and know from practice is that just 2 to 4 cSt variation in viscosity can mean the difference between a buttery smooth shift and having to slow down to drop into gear, especially in cold weather.

 

[SubLGT]

Originally Posted By: Yuk
Originally Posted By: SubLGT
Brookfield Viscosity, at -40degC:

RLI: 115,000

Amsoil: 43,595


What is the practical, felt difference between 115,000 and 43,595 @ -40ºC? Are we talking a spoon in peanut butter vs a spoon in water?


One feels like a spoon in 100% peanut butter, the other feels like a spoon in 50% peanut butter/50% peanut oil.

 

[Gary Allan]

I keep having nagging notions of Egon describing the 57' Twinkie

 

[JoeFromPA]

FYI - AMSOIL 75w110 Severe Gear(what I just put in my Legacy GT....seperate thread starting on that) has a Brooksfield rating of 118,000....

so I'm hoping 118,000 is not like chunky peanut butter after it's been left out for a few weeks...

Joe

 

[tdi-rick]

I'm glad I only have to worry about -7*C, and our 'cold' weather is over for another year.

 

[bruce381]

""If you are not just pulling my leg, it would seem to me that the viscosity difference between pudding to pancake batter is not that great. Is it?"'

Pancake batter will pour and flows tho thick, pudding will NOT flow a spoon dipped in will leave a hole which would you rather have in your gear box?

 

[Yuk]

Originally Posted By: bruce381
""If you are not just pulling my leg, it would seem to me that the viscosity difference between pudding to pancake batter is not that great. Is it?"'

Pancake batter will pour and flows tho thick, pudding will NOT flow a spoon dipped in will leave a hole which would you rather have in your gear box?



Hmm... Well since you put it that way...

 

[MolaKule]

Quote:
It also appears to me, that the specs further support the use of BioSyn 75W-90 in MTs because the BioSyn has a viscosity of 15.7 cSt and not 18 cSt, like rear end lube.


And the Brookfield viscosity shows how much torque is required to move a fluid at low temperature; torque is correlated to viscosity.

The lower the value the better for MT fluids and ATF fluids.