The truth about differential and transfer case fluids

I want to change the rear differential oil of my 2015 TRD Sport MT

I read on TW that it does not require LSD additive like my previous 2008 did, because it is not a real LSD

Is it correct?

 

Check your owners manual, but I believe you are correct that no LSD additive is required for 2015’s rear differential.

 

Here is what I personally recommend for the transfer case:

https://www.amsoil.com/p/manual-synchromesh-transmission-fluid-5w-30-mtf/?zo=515729

 

I’ve used Mobil1 or Valvoline Synthetic 75w90 in the diffs and TC since new. I change at ~30k intervals, but I’ve gone over that without much worry.

 

I've had the original transfer case fluid since my truck was new so that would be 15 years.

However my transfer shifts so smoothly and quickly in and out of 4wd so I'm hesitant to change it. My 2006 Tacoma's transfer case even shifts better that my 2018 4runner. My 4runner takes a while before it shifts in or out of 4wd.

 

DIY and synthetic... great "how to's" in the upper section.

 

That's a much lighter weight than the diff fluid specs, any particular reason you go with this particular fluid? I'm using Amsoil in the rear, and after 2 changes with a cheap fluid in the front, i'm ready to go with the Amsoil up front as well. All this after a regear and backcountry 3k mile trip. Might as well swap out the transfer case while I'm at it and doing a bit of reading first.

 

TC does not see the loads a differential sees - different gear loading, materials, interface, heat, etc - no need at all for heavy gear oil.

Oddly the Amsoil MTF is more viscous than the factory fluid. Factory is a really ultra thin oil.

 

Right, I knew it was a 75w LF and not the 75-90, but just curious since Toyotas fluid is so damn expensive. I can't see paying what they charge, but like Amsoil, and you reco'd the MT which I'm inclined to use. Just wanting to do it right without buying Toyota's fluid

 

To each h

This is what Amsoil recommends. Same lube as front and rear differentials.