Gear oil weight

[astraelraen]

This has probably been asked a million, billion times.

But, is there any reason not to use 75w90 gear oil in differentials speced for 80w90?

It seems that 80w90 is pretty hard to find in anything other than conventional or blended oils. Whereas 75w90 is very common in over the counter synthetics.

I already bought some Mobil 1 75w90 so don't tell me no

This is used in a Mazda CX7 AWD. Front transfer case & rear differential call for 80w90.

 

[Chris71]

I use mineral-based in my rear differential and it's always been 80w-90.I've never seen mineral in 75-90.

 

[Johnny]

The Mobil 1 75W-90 is a very good product. It should work well for you.

 

[aquariuscsm]

My FSM calls for 80W90 in the rear diff. I`m gonna order some Amsoil 80W90 from Pablo here soon.

 

[bruce381]

""But, is there any reason not to use 75w90 gear oil in differentials speced for 80w90?""

No