Dino for me. Been there done that.
Gear oil recommendation - Differential (2 Viewers)
- Thread starter AFei
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I used redline synthetic in all three places about 20k miles ago. Have always run them in my BMWs but since I had to buy 2 gallons to service the whole truck it was kinda expensive.
As for rear LSD, my 1998 has 250k+ miles and I think my limited slip diff still functions.
My transfer case started weeping soon after switching to Mobil 1 - 190k on the clock
Going to try going to the lucas 80w-90 and see if the weep stops instead of tearing open my transfer case
diffs appear fine though
Going to try going to the lucas 80w-90 and see if the weep stops instead of tearing open my transfer case
diffs appear fine though
Don't you have a selectable locker and not a LSD?
98-99 LX has LSD rear and LCs had electronic lockers. I do hear that Locked LC rears are a direct swap for LX rear (the whole axle) but I can't seem to find any for a reasonable price anywhere.
300V or Motylgear?
I now have a selectable rear locker instead of LSD and have switched to SuperTech (Walmart brand) dino oil.
Syn Gear Oil Article - Machinery Lubrication
==================================
Extended Oil Change Intervals Using Synthetic Oils
Synthetic oils have better resistance to aging and high temperatures and a longer service life than mineral oils. Depending on the base oil (SHC or PAG), the oil change intervals may be three to five times longer at the same operating temperature.
Approximate oil change intervals of gear oils at an operating temperature of 176°F (80°C) are:
The following comparison of test results illustrates this advantage. Three lubricants were tested in a splash lubricated worm gear test rig.
The test records show the following oil sump temperatures after 300 operating hours:
Mineral oil: 230°F (110°C)
SHC: 194°F (90°C)
PAG: 167°F (75°C)
The life extension factors of synthetic oils as compared to mineral oil are as follows:
Mineral oil = 1
SHC = 9.5 times longer
PAG = 31 times longer
==================================
Extended Oil Change Intervals Using Synthetic Oils
Synthetic oils have better resistance to aging and high temperatures and a longer service life than mineral oils. Depending on the base oil (SHC or PAG), the oil change intervals may be three to five times longer at the same operating temperature.
Approximate oil change intervals of gear oils at an operating temperature of 176°F (80°C) are:
- Mineral oil: 5,000 operating hours
- SHC oil: 15,000 operating hours (extension factor 3)
- PAG oil: 25,000 operating hours (extension factor 5)
The following comparison of test results illustrates this advantage. Three lubricants were tested in a splash lubricated worm gear test rig.
The test records show the following oil sump temperatures after 300 operating hours:
Mineral oil: 230°F (110°C)
SHC: 194°F (90°C)
PAG: 167°F (75°C)
The life extension factors of synthetic oils as compared to mineral oil are as follows:
Mineral oil = 1
SHC = 9.5 times longer
PAG = 31 times longer
For front and rear diff if open use SAE 90 since that is the actual spec for the 100 series and transfer put motylgear 75w-90 I currently am running everything motul and the LC has been running really smooth
Awesome, thank you!
My '06 LC drivetrain was serviced by the previous owner, but unfortunately at Jiffy Lube... Fortunately Jiffy didn't mess with the transmission and I was able to get that done right after my purchase.
Jiffy used Mobil HD Plus 80W-90 in front and rear diffs and the transfer case. That viscosity is OK for the diffs but a little thick for the transfer case. Mobilube HD Plus seems to be intended for heavy duty applications "These lubricants are engineered for performance in heavy-duty commercial transmissions, axles and final drives..."
Here is the issue as I see it: The Mobilube HD 80W-90 has a viscosity of 139 cSt @ 40ºC, and 14.5 cSt @ 100ºC (don't know the operating temp of those differentials, if anyone knows please comment). The pour pont is -27ºC.
None of this was a problem in my previous location of Burbank, CA (rarely see winter lows below 40ºF, and sometimes see summer highs of 107ºF !) . But I now live in Portland, Maine. The average low temp in January is 13ºF (-10ºC), and mean minimum is -10ºF (-23ºC), which is pretty close to the pour point of the Mobilube 80W-90.
I don't like the idea that on cold winter mornings my differential and transfer case oil will be more like a thick grease and won't be lubricating effectively until the gears warm up.
Going with RedLine 75w-90 gives a viscosity of 112 cSt @ 40ºC and 16.1 cSt @ 100ºC (viscosity index 155) and most importantly a pour point of -45ºC, well below any low temps I am likely to see. This is typical of good synthetic gear lubes: The have both a higher viscosity at 100ºC and a lower viscosity at 40ºC.
Another option is the Motul Gear 300 (an Ester based synthetic) which I have used in my BMW differentials in the past. This is a 75W-90 with an viscosity index of 222 (!), resulting in viscosity of 73 mm2/s @ 40ºC and 15 mm2/s @ 100ºC, and a pour point of -60ºC (!!). I remember the Gear 300 being pricey. For the BMW differentials less than 2 liters were needed.
I notice that the factory spec is 75W-90 for the transfer case and 80W-90 for the differentials. So for some reason Toyota prefers a slightly thicker oil in the differentials.
My plan is to change the gear lubes before the low temps go below freezing. At that time the gear oils will have nearly 20k miles on them. A bit early to change, but seems worth it.
From what I'm reading here, the only potential issue is oil leaks from the diffs due to the thinner oil. My LC only has 130k miles on it, so hopefully those seals are still pliable. Anything else I should be considering?
Jiffy used Mobil HD Plus 80W-90 in front and rear diffs and the transfer case. That viscosity is OK for the diffs but a little thick for the transfer case. Mobilube HD Plus seems to be intended for heavy duty applications "These lubricants are engineered for performance in heavy-duty commercial transmissions, axles and final drives..."
Here is the issue as I see it: The Mobilube HD 80W-90 has a viscosity of 139 cSt @ 40ºC, and 14.5 cSt @ 100ºC (don't know the operating temp of those differentials, if anyone knows please comment). The pour pont is -27ºC.
None of this was a problem in my previous location of Burbank, CA (rarely see winter lows below 40ºF, and sometimes see summer highs of 107ºF !) . But I now live in Portland, Maine. The average low temp in January is 13ºF (-10ºC), and mean minimum is -10ºF (-23ºC), which is pretty close to the pour point of the Mobilube 80W-90.
I don't like the idea that on cold winter mornings my differential and transfer case oil will be more like a thick grease and won't be lubricating effectively until the gears warm up.
Going with RedLine 75w-90 gives a viscosity of 112 cSt @ 40ºC and 16.1 cSt @ 100ºC (viscosity index 155) and most importantly a pour point of -45ºC, well below any low temps I am likely to see. This is typical of good synthetic gear lubes: The have both a higher viscosity at 100ºC and a lower viscosity at 40ºC.
Another option is the Motul Gear 300 (an Ester based synthetic) which I have used in my BMW differentials in the past. This is a 75W-90 with an viscosity index of 222 (!), resulting in viscosity of 73 mm2/s @ 40ºC and 15 mm2/s @ 100ºC, and a pour point of -60ºC (!!). I remember the Gear 300 being pricey. For the BMW differentials less than 2 liters were needed.
I notice that the factory spec is 75W-90 for the transfer case and 80W-90 for the differentials. So for some reason Toyota prefers a slightly thicker oil in the differentials.
My plan is to change the gear lubes before the low temps go below freezing. At that time the gear oils will have nearly 20k miles on them. A bit early to change, but seems worth it.
From what I'm reading here, the only potential issue is oil leaks from the diffs due to the thinner oil. My LC only has 130k miles on it, so hopefully those seals are still pliable. Anything else I should be considering?
Can I use 75W-90 diff oil?
The manual specs SAE 90 for the F/R diff and 75W90 for the t-case. Can I hurt it by putting the same stuff in all the diffs? I want to switch to M1.
forum.ih8mud.com
Check this out:
http://gvsets.ndia-mich.org/documen...y%20Axle%20Efficiency%20Test%20Stand.pdf
H/T to the guys at bobistheoilguy.com. Very thorough test was done for the U.S. Army. The result for the HMMWV (closest to our LC's the other were heavy armored trucks) is that 75W-90 is good for about a 0.5% increase in fuel efficiency over 80W-90. 75W-140 had an advantage in heavy load low speed conditions.
What I'm wondering: Would the efficiency gain "stack" since there are 3 differentials, or would it just be 0.5% improvement overall?
For the test linked above, they tested individual axles (which I assume means just a single diff in the case of the HMMWV).
http://gvsets.ndia-mich.org/documen...y%20Axle%20Efficiency%20Test%20Stand.pdf
H/T to the guys at bobistheoilguy.com. Very thorough test was done for the U.S. Army. The result for the HMMWV (closest to our LC's the other were heavy armored trucks) is that 75W-90 is good for about a 0.5% increase in fuel efficiency over 80W-90. 75W-140 had an advantage in heavy load low speed conditions.
What I'm wondering: Would the efficiency gain "stack" since there are 3 differentials, or would it just be 0.5% improvement overall?
For the test linked above, they tested individual axles (which I assume means just a single diff in the case of the HMMWV).
Does it really matter? Even if you "stacked" the benefits of 3 gear boxes you are still talking about an almost imperceptible increase in mpg,<0.25 mpg assuming an average mpg of 15. And those results come from optimized conditions using a test stand and not necessarily in real world (on road) conditions. Their goal was to improve the economics over the large military fleet, not the individual vehicle. We don't drive these for efficiency. I guess if everyone with a 100 changed to 75W-90 there will be small benefits to overall environmental damage due to lower fuel consumption and emissions over a large fleet but the individual gains will be too small to notice.
It would compound, not add. i.e. 1.0025 * 1.0025.
Different differentials have different hypoid offsets and different gear ratios have different efficiency characteristics too. So don't expect an equivalent improvement.
All this paper really tells us is (shockingly!) that lower viscosity gear oils tend to save fuel. Its not like they have a tribological engineer evaluate the gear teeth afterwards, though, and I'd bet most people on mud would care more about longevity than fuel efficiency.
For what it's worth, I don't think heavier gear oils will necessarily protect better.
Right, that makes sense.
If you're going to change gear oils anyway, and you need a lighter "W" number anyway (for cold weather flow), then the 0.5% efficiency increase per diff is "free". Small MPG increase but no downside.
The SAE 90 hot viscosity will protect as well as the 80W-90 oil.
Mobilube HD 80W-90 14.5 cSt @100ºC (dino - whats in my diffs now)
Amsoil Severe Gear 75W-90 15.9 cSt @100ºC (synth)
I changed both diffs and T-case to 75w-90 synthetic with a new oil brand Ultra1Plus out of Florida last year....since then, I swear my truck has more resistance when moving... especially when it is cold out. My MPG also shows it until the truck is fully warmed up.
The other potential reason is my rear diff had moisture in it and I sprayed brake cleaner into the diff and had it drain...then ran cheap diff fluid for a day and then drained again to clean it out then topped off with good stuff. My concern is maybe I got some debris into the gears... probably need to have a look.
So two things: 1) I went to 75w-90 synthetic and am getting worse mileage and 2) did I get debris into my rear gears!!!
