Toyota Tacoma LSD - Conventional or Synthetic Blend 80w90

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Looking for a quality conventional or synthetic blend 80w90 gear oil for a finicky Tacoma LSD. No synthetic. I see ST and other store brands, but curious if there are any top-tier options out there.

Thanks.
 
I have always run Valvoline in my Nissan's front diff's that call for 80W90. I have no idea how great it is - its likely a pretty low stress application. The oldest one has 420K miles now - always valvoline, no issues. https://www.rockauto.com/en/moreinfo.php?pk=10411189&cc=0&pt=11394&jsn=495

Mobil still makes one believe it or not if you can find it. I am partial to Exxon products but I have never found a easy place to buy it. https://www.mobil.com/en-gu/commercial-vehicle-lube/pds/sp-xx-mobilube-hd-80w-90

80W90 is as old as the hills and growing up we ran 80W90 in all the equipment and the key seemed simply to be to refresh it frequently and we didn't have issues. I think it shears down pretty quick compared to synthetic hence the old 30K change interval's in diff's.
 
Why not synth? Isn't it spec'd for 75w-85 LSD?
The older ones are spec’ed for 80w-90 below 0F or SAE90 above 0. These units seem to be exceptionally finicky. For unknown reasons, using synthetic gear oil with friction modifier carries a high likelihood of chatter issues.
 
Did you try a little thicker oil? Or 75w-90 LSD in synth?
This isn’t my truck. I’d rather not have a comeback since I service it for free. I have never experimented in this application; it’s my first rodeo. Just trying to avoid issues.
 
The older ones are spec’ed for 80w-90 below 0F or SAE90 above 0. These units seem to be exceptionally finicky. For unknown reasons, using synthetic gear oil with friction modifier carries a high likelihood of chatter issues.
What kind of diff is it? Is it limited slip?

I used to add a Mopar friction modifier to the fluid in my Jeep years ago (limited slip). Does Toyota offer something similar?

Since your worried and its not your car - maybe OEM. Although I hate to imagine how much Toyota wants for gear oil. $25 a quart I bet.
 
What kind of diff is it? Is it limited slip?

I used to add a Mopar friction modifier to the fluid in my Jeep years ago (limited slip). Does Toyota offer something similar?

Since your worried and its not your car - maybe OEM. Although I hate to imagine how much Toyota wants for gear oil. $25 a quart I bet.
Mechanical LSD.

https://www.tacomaworld.com/threads/beware-changing-lsd-lube.93117/page-3

For unknown reasons, synthetic oil causes any pour-in LSD additive to not function sufficiently in these differentials.
 
+1 on Castrol 80w90, been using it (and under its prior name Hypoy C) for many years in a Tundra with a similar design and same requirement, always functions perfectly for 50k intervals
 
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