80w90 in rear diff

[4central]

Hi All,

I had my first oil change at 45K miles for the rear diff. My Toyota dealership messed up and put 80w90 oil ( good chance conventional) in rear diff. I asked multiple times, and wanted original 75W85 oil. They even brought the cans, and said it is gonna cost $200. I said ok, please go ahead. Still they did what they believe is the best, at least they did charge much much less for this.

My question, do I need to worry about using 80w90? So far for 20 miles, no issues, felt a bit more responsive, but can be simply nothing.

 

[83Mule]

No!.....it's not spec and it will run hotter. Also it's $6 a quart and 1/2 hour of labor so what did they charge for that?! Also worse gas mileage.

 

[TOYO74]

In my opinion: There is almost no difference in viscosity between 75w-85 and 80w-90. Secondly, at operating temp the viscosity is the same. Don't see how using 80w-90 will cause the diff to "run hotter".

Remember, asking a question about oil always starts a shouting match, so expect multiple opinions. I can only say what I would do--don't worry about it.

 

[MaddoxPics]

I did 75-90.

 

[GripT4R]

It will be perfectly fine.

 

[T4R2014]

Don't be ridiculous. It's a Toyota diff. 80W90 has worked for years. I raise my eyebrows hearing 75W85.

 

[Jivewalker]

I run amsoil 75w-90 with no issues.

 

[2016 4Runner SR5]

I run M1 synthetic 75-90 in the diffs without an issue. I believe original fill is conventional but synthetic is definitely the way to go. DO it yourself, takes 15 minutes to do the rear diff, 30 to do the front since you have to drop the skid plate. 1 hour including clean up and you're done.