Gear oil recommendation - Differential (1 Viewer)

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Where researching for the gear oil for the differentials on my 2004 LX470, I got a little bit lost.

Some says 75W-90 full synthetic gear oil should be good for all Transfer Case, and Differentials, while somewhere specially mentioned 80W-90 should be used for diffentials. And then saw the attached document which recommends against synthetic oil for differentials.

So, should I:
  1. Use dino gear oil or synthetic oil for differential?
  2. 75W-90 or 80W-90? apparently, it's almost impossible to find synthetic 80W-90 gear oil at all
Thanks!
 

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Use what the FSM states for your climate. I use 75-90 Valvoline Synthetic as its inexpensive and pretty much always available at any store. I also use Valvoline for all other fluids except oil change. Dont drive yourself crazy overthinking it... :)
 
^ Ditto.
 
:princess:'s '01 LX has used M1 75W-90 for the last 10 years, ~90K miles. It goes in both ids and the transfer case, and given relatively low yearly mileage it's changed every 2 years. Knock wood, but zero issues.

About the ecgs ring gear article download, I'd just consider the source. I'd also think about the tons of high-end vehicles that use synthetic fluids from the first fill on the assembly line.
 
How much fluid would I need to fill all 3? was going to pick up a gallon of the lucas oil 75w90
 
Avoid synthetic. Want the best? Try Schaeffer dino.
 
my mechanic 10 years ago suggested staying with dino gear oils for somewhat vague reasons, and change them periodically. So I do that. Having oil in there is perhaps the only truly important factor. : )
Gil
 
Slightly different angle but relative just the same: Curry would not honor warranty if synthetic was used in their diffs. Most OEM have gone back to dino lube in diffs...

I have found synthetic to be troublesome to axle, pinion & main seals. I continue to use Amsoil in the engine (rethinking this as I had the main seal swapped at about 190k total on the clock) but for diffs & t-case its dino for me. YMMV but based upon my 200k miles I've put on my spressoWAGON meself.
 
Avoid synthetic. Want the best? Try Schaeffer dino.

I was looking on their site Dan and couldn't easily find their dino blend. Do you happen to have a link? Here's their gear lubes.
 
^
Their 209 Moly Universal Gear Lube. I believe they still offer their 214 80/140 in conventional non-syn also.



Lucas is good too: More widely available for over-the-counter sale/pick-up and less expensive. Plenty good, especially for those that get their diffs/t-case submerged in water and thus doing more frequent drain & fills than 30k OEM PM frequency.
 
@spressomon Interested to learn more about your (or others) bad experiences with SYN gear oil. I run RP 85/140 Syn in my 3rd after locker install (about 2yrs and 20k miles ago), before the locker was M1 75/90. SYN was recommended by both installer and locker manufacturer.

"troublesome to axle, pinion & main seals" Are you saying its prone to cause seal leaks or deterioration or failure due to synthetic gear oil. Not challenging you but wanting to learn more about it.
 
Mostly anecdotal (not quite sure how I'd prove my theory with 100% conviction...) but I have experienced a spate of rear axle seal failures while running Amsoil gear lube (both viscosities including 110-140w for about 8-9 years worth of running) along with front diff pinion seal weeping. To date, and its been at least 4-years since switching the rear diff over to dino gear lube, I've not experienced the re-occuring rear axle leak issue.

A few months ago I noticed the front diff pinion seal weeping. Not enough to drip onto the driveway but plenty of diff lube all over the tail of the diff housing and skid plate. I swapped in Lucas 80/90 (tried to source Schaeffer but no one local to me carried it...) and the seep has all but gone away.
 
I run Mobil One, 75w-90 synthetic in the front, center and rear.

I am planning to use the exact same for all 3 of my LX470 (Mobilube 1 SHC 75W-90).
But I have read that the rear diff needs limited slip.
That would not create any problems?
You are not using that?
 
I am planning to use the exact same for all 3 of my LX470 (Mobilube 1 SHC 75W-90).
But I have read that the rear diff needs limited slip.
That would not create any problems?
You are not using that?

My LC doesn't have a limited slip rear so I didn't need to factor that in. Maybe another member with a similarly equipped LX could chime in?

What spec oil does your owner's manual call for in the rear diff? If in doubt, that's what I would go with.
 

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