Hi all. The stores around here don't stock 75w90 gear oil, as the manual says to use in the transfer case and front diff.

The stores have plenty of 80w90

Could it be because of the mild climate here? It never gets lower than 15 F. I see the pour point of 80w90 is -16 F

Is it ok to use 80w90 instead of 75w90?

 

The slightly heaver cold point spec gear oil will not hurt anything. Use it.

 

You don't say where you live.

Where I live I can't find anything but 75W-90.
So even the synthetic is 80W-90?

 

Has anyone ever run 80w90 in their transfer case? Usually that's the 75w stuff that's GL-4. Front diff prob wouldn't hurt. Both diffs take GL-5 oils.

Colder climate would definitely be a factor against going thicker.

 

The difference in 75w-90 and 80w-90 is irrelevant in ordinary service.

It might make some small difference in machines regularly operated in conditions below 0 degrees F. Even then, not much.

 

I run Sta-lube 85w90 in my gear-driven RF1A t-case and it's fine all year round in NE Ohio. I don't know about the later chain-driven t-case's, they might be more picky.

 

Thanks for the replies so far.

Seattle area (normal lowest low is 20F, rarely gets to 15, never below zero)

I may take occasional trip to zero degree areas but not below the pour point -16F

3rd Gen 4Runner (2001) so I assume it's gear TC not chain.

 

I wasn't able to find the t-case model # for a 2001 4runner with a quick internet search, but it's chain-driven for sure.

Even so, 80w90 will be good in your climate like everyone's already said.

 

I had most of a 55gallon drum of 85/140 gear oil I used in all my gear boxes for years .

The only difference I noticed on those cool days around 0 F with a steady 20 mph breeze things were a little stiff after sitting 10 hours plus