Transfer Case oil

Per Toyota 75w90 is perfectly fine to use. I even called several local Toyota and Lexus dealerships and they all say they buy 75w90 in bulk for all diffs and transfer cases.

Here’s a few screenshots of my emails with Toyota Corp.

I put 75w90 in the TC of my 4runner, gx460 and tundra. No issues.

 

Thanks..

 

This is what I changed to at 30k and to me the truck goes in and out of 4WD better.

 

Very interesting considering that TIS still only says 75w. I'm far from an oil snob and dont use 75w85 or 0w20 like Toyota says but I have stuck with the Toyota 75w in the transfer case because of it's clear difference in VOA from typical 75w90 and the fact that its recommendation came from the change of transfer case to BorgWarner in 2014 and not something directly related to CAFE standards like 75w85 or 0w20. I currently have a little over 50,000 miles and have only changed my TC fluid once and used the Toyota fluid and plan to only do it every 30,000 so figured the extra money spread out over 30,000 miles isn't a big deal to ensure reliability of 4x4. I regularly use 4x4 in the winter months and need it to work. 75w90 is a much thicker oil than the Toyota 75w and there have been posts on this forum about people who have used 75w90 having issues getting into and out of 4x4 so that's what solidified my choice in fluid and I have had 0 issues going into and out of 4x4 smoothly and quickly so I'll stick with the 75w for now since I already have a couple cans ready for the next change but I have no problem with people using 75w90 considering it's clearly what most dealers use but lets not forget how terrible dealers actually are, they are using it out of convenience and cost saving and if they went by the manual (TIS) then they should be using 75w. If there are people who are using 75w90 without issue in cold weather I'm all ears. I think if you're in a warm climate though 75w90 would be the way to go.

 

I've tried both

$39 75w-90 GL-5 Limited Slip, Ultra Long Drain 500k Miles, Manual Transmission, Gear/Differential Lubricant (1 Gallon)

75w-90 mobil one and the Toyota 75W. My experience shows that the transfer case seems to shift faster into and out of engagement with the Toyota 75W.

i bite the bullet and use the 75W in both my 4runner and tundra.

 

You know. What you did seems like a pretty good way of going about it. Try the 75w90 in and see what ya think. If you don’t like it then get the 75w. I am about to go through all changeouts with 75w90. Last one I used all the proper ravenol. If I don’t like it then swap. It is certainly easy enough.

 

^^^ This. Transfer case oil lasts a long, long time. There’s little to no heat and a fraction of the shear forces found in the rear differential. 30k makes sense for the diff but it’s just a waste of oil changing the transfer case at that interval. I dumped the transfer case oil in my Tacoma at 90k and it was like new - I could have poured it back in and rolled another 50k.

Think of all the Toyotas out there that get beat to hell for hundreds of thousands of miles without ever having the transfer case oil changed. Transfer case failures are pretty few and far between AFAIK.

That said, fresh oil can’t hurt. And it looks good on the maintenance log

 

I changed it at 50k in my Tacoma. Waste of time and money. Same deal. What j drained looked like it came straight out of the bottle. If I lived in snow country and used 4wd a lot I might change it more often then what I do.