75w 90 vs. 80 w90 in rear diff?

[SIKHILUXSURF]

hey guys i was wondering if it is such a big deal to use 75w90 in the rear diff on our 3rd gens when the recommended weight is 80w90? i wanted to use 75w90 redline gear oil in the runner but they dont make a 80w90 oil that is recommended in the rear diff. will i notice any big differences or mess up the rear diff by using 75w90 instead of 80w90?

 

[rdgt4r]

i chose to do 75w140 RP and i was supposed to notice a mpg drop but didnt get one plus i have not had any negative response to using it 15k miles later. I dont think you will have any adverse effects by using 75w. ill let others chime in on this one and get opinions on the topic.

 

[JohnsD90]

i did 75w90 when i replaced the 3rd member, and i hadnt really driven it before that, and its been runnin fine after 4k miles.

 

[BigFishAllDay]

Check your owners manual's fluid specs section. 75w90 is reccommended for applications where the truck will not be used in extreme cold... 80w90 is reccomended for use in colder climates... think Canada, Alaska. I think the temperature cutoff where you want to start using the 80w90 was something like 10 degrees F (meaning that the truck will regularly be driven in an environment where that is the ambient temperature).

I just changed out my differential fluids, and I used 75w90 redline... I called redline and that's even what they reccommended.

 

[LINY4Runner]

I don't think 80w-90 is made in a synthetic. Seems like the thickest they could get it is 75 lol

Like BigFish said, as long as you're not wayyy up there, constantly trekkin through snow (ahem alaskaman90) you should be okay with 75/90


Also, look into adding a half quart of Lucas Oil Stabilizer to your diffs and TC...stuff works GREAT!

 

[ChildrenOfBodom]

This thread could not have come at a better time!

I have a list and today I was on redlineoils.com seeing the same thing you saw.

Thanks for answering my question!!!!!!!

75W90 GL-5 is only 13.95 a quart from them, too.

 

[hyperduc]

Most if not all fluid recomendations are based or at least biased by EPA evaluations, this means that the fluid recommended is often not the best performing fluid you can use for that particular application.

 

[rdgt4r]

Most if not all fluid recomendations are based or at least biased by EPA evaluations, this means that the fluid recommended is often not the best performing fluid you can use for that particular application.

Your correct in addition to that, depending on the environment the vehicle is driven in and how it is driven ie. off highway, steep terrain, towing etc etc. If you read what a 75w140 will do for you or what a 80w-90 you can customize your fluid to better suit what type of driving you encounter. I have no doubt that a 80w-90 would be great for city/highway and a little off road driving. But me for instance we can have over 30 days over 105 degrees that and add steep hill climbs the 75w140 has held up great for me. Like i said personal preference and your driving style will ultimately decide whats best for you.

Differential gear oil question - YotaTech Forums

 

[SIKHILUXSURF]

i ended up getting a good deal on some Lucas diff oil and motor oil for the runner at 5 bucks a quart of 5w30 and at 6 bucks a bottle and bought 3 bottles of 75w90 and 3 of 80w90 i guess i will try redline next diff change.