Using 75w85 in place of 75w90 (In Differentials)

[kyoo]

Thinking about making this switch, primarily for drag reasons. Red Line makes a very nice 75w85, am considering giving it a shot in the transfer case and rear differential of my '11 V6 Rav4 4wd.

Logic is the car isn't driven hard at all - daily duties for the most part, no towing, etc. What kind of problems could I see moving to this lighter fluid? I imagine if it's still high quality, which Red Line is, and the film strength remains in tact, I should be good?

 

[demarpaint]

I don't see it as any problem at all under the conditions you described. The RL product you plan on using is a top quality product.

 

[Rand]

That's a very thin gear oil 11.5CST@100C vs 16.1 for 75w90

Would be ok in winter.

Not sure I could recommend it for summer use..
even if you only drive it hard 1% of the time do you want to change it out before driving hard?
In the Rear Diff,
They only recommend 80wt gear oil for under 0f use.
90wt or 80w90 is recommended above 0F

page 461 owners manual.

In The transfer case they only recommend straight 90wt gear oil over 0F, not even 80w90.

Not worth it.. you would pickup less than .5 mpg

 

[kyoo]

Originally Posted By: Rand
That's a very thin gear oil 11.5CST@100C vs 16.1 for 75w90

Would be ok in winter.

Not sure I could recommend it for summer use..
even if you only drive it hard 1% of the time do you want to change it out before driving hard?
In the Rear Diff,
They only recommend 80wt gear oil for under 0f use.
90wt or 80w90 is recommended above 0F

page 461 owners manual.

In The transfer case they only recommend straight 90wt gear oil over 0F, not even 80w90.

Not worth it.. you would pickup less than .5 mpg


Thank you for the input - the Evo requests the same (straight 90wt) but happily runs on 75w90. The sticker on the t-case actually has 80w90 on it. Given how thin it is at operating temp, as you have noted, I think I will stick with the 75w90 then.

 

[CT8]

Thicker is better.

 

[zeng]

Originally Posted By: CT8
Thicker is better.


CT8 ,
I would agree with you beyond any doubt

........ but hey look ......
It is said to be not true here ......
https://bobistheoilguy.com/forums/ubbthreads.php/topics/4008698/Re:_Diaqueen_%28now_MZ320345%29_SA#Post4008698
God bless our ...... ?

 

[kyoo]

Originally Posted By: zeng
Originally Posted By: CT8
Thicker is better.


CT8 ,
I would agree with you beyond any doubt

........ but hey look ......
It is said to be not true here ......
https://bobistheoilguy.com/forums/ubbthreads.php/topics/4008698/Re:_Diaqueen_%28now_MZ320345%29_SA#Post4008698
God bless our ...... ?

smh you again? thicker is not always better, or else all oils would be straight weights, as you were heavily missing the point in in that thread. the lighter at cold temps, the better, because it will still be thicker than what the viscosity at operating temp is. smh.

 

[bulwnkl]

You know, it's curious...

Honda recommends SAE 90 or 80W90 in the transfer case of the Honda Ridgeline. They also recommend Honda HGO-1 gear oil, etc., etc....which is a 75W85.